\cfg{ps-filename}{puzzles.ps}
\cfg{pdf-filename}{puzzles.pdf}
+\define{by} \u00D7{x}
+
+\define{dash} \u2013{-}
+
This is a collection of small one-player puzzle games.
-\copyright This manual is copyright 2004 Simon Tatham. All rights
+\copyright This manual is copyright 2004-5 Simon Tatham. All rights
reserved. You may distribute this documentation under the MIT licence.
See \k{licence} for the licence text in full.
find (or perhaps invent) further puzzle games that I like, they'll
be added to this collection and will immediately be available on
both platforms. And if anyone feels like writing any other front
-ends - PocketPC, Mac OS pre-10, or whatever it might be - then all
-the games in this framework will immediately become available on
-another platform as well.
+ends \dash PocketPC, Mac OS pre-10, or whatever it might be \dash
+then all the games in this framework will immediately become
+available on another platform as well.
-The actual games in this collection were mostly not my invention; I
-saw them elsewhere, and rewrote them in a form that was more
-convenient for me. I do not claim credit, in general, for inventing
-the rules of any of these puzzles; all I claim is authorship of the
-code (or at least those parts of the code that weren't contributed
-by other people!).
+The actual games in this collection were mostly not my invention; they
+are re-implementations of existing game concepts within my portable
+puzzle framework. I do not claim credit, in general, for inventing the
+rules of any of these puzzles. (I don't even claim authorship of all
+the code; some of the puzzles have been submitted by other authors.)
This collection is distributed under the \i{MIT licence} (see
\k{licence}). This means that you can do pretty much anything you like
and via \I{keys}keyboard shortcuts, in addition to any game-specific
actions.
+(On Mac OS X, to conform with local user interface standards, these
+actions are situated on the \I{File menu}\q{File} and \I{Edit
+menu}\q{Edit} menus instead.)
+
\dt \ii\e{New game} (\q{N}, Ctrl+\q{N})
\dd Starts a new game, with a random initial state.
-\dt \ii\e{Restart game} (\q{R})
+\dt \ii\e{Restart game}
+
+\dd Resets the current game to its initial state. (This can be undone.)
+
+\dt \ii\e{Load}
+
+\dd Loads a saved game from a file on disk.
-\dd Resets the current game to its initial state. Undo is lost.
+\dt \ii\e{Save}
+
+\dd Saves the current state of your game to a file on disk.
+
+\lcont{
+
+The Load and Save operations should preserve your entire game
+history (so you can save, reload, and still Undo and Redo things you
+had done before saving).
+
+}
\dt \ii\e{Undo} (\q{U}, Ctrl+\q{Z}, Ctrl+\q{_})
\dd Undoes a single move. (You can undo moves back to the start of the
-game.)
+session.)
-\dt \ii\e{Redo} (Ctrl+\q{R})
+\dt \ii\e{Redo} (\q{R}, Ctrl+\q{R})
-\dd Redoes a previous undone move.
+\dd Redoes a previously undone move.
-\dt \I{exit}\ii\e{Quit} (\q{Q}, Ctrl+\q{Q})
+\dt \ii\e{Copy}
-\dd Closes the application entirely.
+\dd Copies the current state of your game to the clipboard in text
+format, so that you can paste it into (say) an e-mail client or a
+web message board if you're discussing the game with someone else.
+(Not all games support this feature.)
+
+\dt \ii\e{Solve}
+
+\dd Transforms the puzzle instantly into its solved state. For some
+games (Cube) this feature is not supported at all because it is of
+no particular use. For other games (such as Pattern), the solved
+state can be used to give you information, if you can't see how a
+solution can exist at all or you want to know where you made a
+mistake. For still other games (such as Sixteen), automatic solution
+tells you nothing about how to \e{get} to the solution, but it does
+provide a useful way to get there quickly so that you can experiment
+with set-piece moves and transformations.
-\H{common-id} Recreating games with the \ii{game ID}
+\lcont{
-The \q{\i{Specific...}} option from the \I{Game menu}\q{Game} menu
-lets you see a short string (the \q{game ID}) that captures the
-initial state of the current game.
+Some games (such as Solo) are capable of solving a game ID you have
+typed in from elsewhere. Other games (such as Rectangles) cannot
+solve a game ID they didn't invent themself, but when they did
+invent the game ID they know what the solution is already. Still
+other games (Pattern) can solve \e{some} external game IDs, but only
+if they aren't too difficult.
-The precise \I{ID format}format of the ID is specific to each game.
-It consists of two parts delimited by a colon (e.g., \c{c4x4:4F01,0});
-the first part encodes \i\e{parameters} (such as grid size), while the
-second part encodes a \i\e{seed}, which determines the \i{initial
-state} of the game within those parameters.
+The \q{Solve} command adds the solved state to the end of the undo
+chain for the puzzle. In other words, if you want to go back to
+solving it yourself after seeing the answer, you can just press Undo.
-You can specify a new ID (or just a seed) here. Pressing \q{OK} starts
-a new game with the specified ID (whether you changed it or not).
-Pressing \q{Cancel} returns to the current game.
+}
-You can also use the game ID (or just the encoded parameters) as a
-\i{command line} argument; see \k{common-cmdline} for more detail.
+\dt \I{exit}\ii\e{Quit} (\q{Q}, Ctrl+\q{Q})
+
+\dd Closes the application entirely.
-Game IDs are portable across platforms; you can use a game ID
-generated by the Windows version of a game on the Unix version, etc.
+\H{common-id} Specifying games with the \ii{game ID}
+
+There are two ways to save a game specification out of a puzzle and
+recreate it later, or recreate it in somebody else's copy of the
+same puzzle.
+
+The \q{\i{Specific}} and \q{\i{Random Seed}} options from the
+\I{Game menu}\q{Game} menu (or the \q{File} menu, on Mac OS X) each
+show a piece of text (a \q{game ID}) which is sufficient to
+reconstruct precisely the same game at a later date.
+
+You can enter either of these pieces of text back into the program
+(via the same \q{Specific} or \q{Random Seed} menu options) at a
+later point, and it will recreate the same game. You can also use
+either one as a \i{command line} argument (on Windows or Unix); see
+\k{common-cmdline} for more detail.
+
+The difference between the two forms is that a descriptive game ID
+is a literal \e{description} of the \i{initial state} of the game,
+whereas a random seed is just a piece of arbitrary text which was
+provided as input to the random number generator used to create the
+puzzle. This means that:
+
+\b Descriptive game IDs tend to be longer in many puzzles (although
+some, such as Cube (\k{cube}), only need very short descriptions).
+So a random seed is often a \e{quicker} way to note down the puzzle
+you're currently playing, or to tell it to somebody else so they can
+play the same one as you.
+
+\b Any text at all is a valid random seed. The automatically
+generated ones are fifteen-digit numbers, but anything will do; you
+can type in your full name, or a word you just made up, and a valid
+puzzle will be generated from it. This provides a way for two or
+more people to race to complete the same puzzle: you think of a
+random seed, then everybody types it in at the same time, and nobody
+has an advantage due to having seen the generated puzzle before
+anybody else.
+
+\b It is often possible to convert puzzles from other sources (such
+as \q{nonograms} or \q{sudoku} from newspapers) into descriptive
+game IDs suitable for use with these programs.
+
+\b Random seeds are not guaranteed to produce the same result if you
+use them with a different \i\e{version} of the puzzle program. This
+is because the generation algorithm might have been improved or
+modified in later versions of the code, and will therefore produce a
+different result when given the same sequence of random numbers. Use
+a descriptive game ID if you aren't sure that it will be used on the
+same version of the program as yours.
+
+\lcont{(Use the \q{About} menu option to find out the version number
+of the program. Programs with the same version number running on
+different platforms should still be random-seed compatible.)}
+
+\I{ID format}A descriptive game ID starts with a piece of text which
+encodes the \i\e{parameters} of the current game (such as grid
+size). Then there is a colon, and after that is the description of
+the game's initial state. A random seed starts with a similar string
+of parameters, but then it contains a hash sign followed by
+arbitrary data.
+
+If you enter a descriptive game ID, the program will not be able to
+show you the random seed which generated it, since it wasn't
+generated \e{from} a random seed. If you \e{enter} a random seed,
+however, the program will be able to show you the descriptive game
+ID derived from that random seed.
+
+Note that the game parameter strings are not always identical
+between the two forms. For some games, there will be parameter data
+provided with the random seed which is not included in the
+descriptive game ID. This is because that parameter information is
+only relevant when \e{generating} puzzle grids, and is not important
+when playing them. Thus, for example, the difficulty level in Solo
+(\k{solo}) is not mentioned in the descriptive game ID.
+
+These additional parameters are also not set permanently if you type
+in a game ID. For example, suppose you have Solo set to \q{Advanced}
+difficulty level, and then a friend wants your help with a
+\q{Trivial} puzzle; so the friend reads out a random seed specifying
+\q{Trivial} difficulty, and you type it in. The program will
+generate you the same \q{Trivial} grid which your friend was having
+trouble with, but once you have finished playing it, when you ask
+for a new game it will automatically go back to the \q{Advanced}
+difficulty which it was previously set on.
\H{common-type} The \q{Type} menu
\i{preset} game settings. Selecting one of these will start a new
random game with the parameters specified.
-The \q{Type} menu may also contain a \q{\i{Custom...}} option which
-allows you to fine-tune game \i{parameters}. The parameters available
-are specific to each game and are described in the following sections.
+The \q{Type} menu may also contain a \q{\i{Custom}} option which
+allows you to fine-tune game \i{parameters}. The parameters
+available are specific to each game and are described in the
+following sections.
\H{common-cmdline} Specifying game parameters on the \i{command line}
The easiest way to do this is to set up the parameters you want
using the \q{Type} menu (see \k{common-type}), and then to select
-\q{Specific} from the \q{Game} menu (see \k{common-id}). The text in
-the \q{Game ID} box will be composed of two parts, separated by a
-colon. The first of these parts represents the game parameters (the
-size of the playing area, for example, and anything else you set
-using the \q{Type} menu).
+\q{Random Seed} from the \q{Game} or \q{File} menu (see
+\k{common-id}). The text in the \q{Game ID} box will be composed of
+two parts, separated by a hash. The first of these parts represents
+the game parameters (the size of the playing area, for example, and
+anything else you set using the \q{Type} menu).
If you run the game with just that parameter text on the command
line, it will start up with the settings you specified.
For example: if you run Cube (see \k{cube}), select \q{Octahedron}
from the \q{Type} menu, and then go to the game ID selection, you
-will see a string of the form \cq{o2x2:911A81,10}. Take only the
-part before the colon (\cq{o2x2}), and start Cube with that text on
-the command line: \cq{cube o2x2}.
+will see a string of the form \cq{o2x2#338686542711620}. Take only
+the part before the hash (\cq{o2x2}), and start Cube with that text
+on the command line: \cq{cube o2x2}.
If you copy the \e{entire} game ID on to the command line, the game
will start up in the specific game that was described. This is
occasionally a more convenient way to start a particular game ID
than by pasting it into the game ID selection box.
+(You could also retrieve the encoded game parameters using the
+\q{Specific} menu option instead of \q{Random Seed}, but if you do
+then some options, such as the difficulty level in Solo, will be
+missing. See \k{common-id} for more details on this.)
+
\C{net} \i{Net}
\cfg{winhelp-topic}{games.net}
\i\cw{NETGAME.EXE} to avoid clashing with Windows's own \cw{NET.EXE}.)
I originally saw this in the form of a Flash game called \i{FreeNet}
-\k{FreeNet}, written by Pavils Jurjans. The computer prepares a
+\k{FreeNet}, written by Pavils Jurjans; there are several other
+implementations under the name \i{NetWalk}. The computer prepares a
network by connecting up the centres of squares in a grid, and then
shuffles the network by rotating every tile randomly. Your job is to
rotate it all back into place. The successful solution will be an
-entirely connected network, with no closed loops. \#{Is it also true
-that a correct solution will not contain any cycles?} As a visual aid,
+entirely connected network, with no closed loops. \#{The latter
+clause means that there are no closed paths within the network.
+Could this be clearer? "No closed paths"?} As a visual aid,
all tiles which are connected to the one in the middle are
highlighted.
\dt \e{Rotate tile clockwise}: right mouse button, \q{D} key
+\dt \e{Rotate tile by 180 degrees}: \q{F} key
+
\dt \e{Lock (or unlock) tile}: middle mouse button, shift-click, \q{S} key
\dd You can lock a tile once you're sure of its orientation. You can
also unlock it again, but while it's locked you can't accidentally
turn it.
+The following controls are not necessary to complete the game, but may
+be useful:
+
+\dt \e{Shift grid}: Shift + arrow keys
+
+\dd On grids that wrap, you can move the origin of the grid, so that
+tiles that were on opposite sides of the grid can be seen together.
+
+\dt \e{Move centre}: Ctrl + arrow keys
+
+\dd You can change which tile is used as the source of highlighting.
+(It doesn't ultimately matter which tile this is, as every tile will
+be connected to every other tile in a correct solution, but it may be
+helpful in the intermediate stages of solving the puzzle.)
+
\dt \e{Jumble tiles}: \q{J} key
\dd This key turns all tiles that are not locked to random
The grid generation in Net has been carefully arranged so that the
barriers are independent of the rest of the grid. This means that if
-you change the \e{Barrier probability} parameter, and then re-enter
-the same game ID you were playing before (see \k{common-id}), you
-should see exactly the same starting grid, with the only change
-being the number of barriers. So if you're stuck on a particular
-grid and need a hint, you could start up another instance of Net,
-set up the same parameters but a higher barrier probability, and
-enter the game seed from the original Net window.
+you note down the random seed used to generate the current puzzle
+(see \k{common-id}), change the \e{Barrier probability} parameter,
+and then re-enter the same random seed, you should see exactly the
+same starting grid, with the only change being the number of
+barriers. So if you're stuck on a particular grid and need a hint,
+you could start up another instance of Net, set up the same
+parameters but a higher barrier probability, and enter the game seed
+from the original Net window.
}
+\dt \e{Ensure unique solution}
+
+\dd Normally, Net will make sure that the puzzles it presents have
+only one solution. Puzzles with ambiguous sections can be more
+difficult and more subtle, so if you like you can turn off this
+feature and risk having ambiguous puzzles. (Also, finding \e{all}
+the possible solutions can be an additional challenge for an
+advanced player.)
+
\C{cube} \i{Cube}
\cfg{winhelp-topic}{games.cube}
\IM{Cube controls} keys, for Cube
\IM{Cube controls} shortcuts (keyboard), for Cube
-This game is played with the keyboard. The arrow keys are used to roll the
-cube (or other solid).
+This game can be played with either the keyboard or the mouse.
+Left-clicking anywhere on the window will move the cube (or other
+solid) towards the mouse pointer.
+
+The arrow keys can also used to roll the cube on its square grid in
+the four cardinal directions.
On the triangular grids, the mapping of arrow keys to directions is
more approximate. Vertical movement is disallowed where it doesn't
make sense. The four keys surrounding the arrow keys on the numeric
\cfg{winhelp-topic}{games.fifteen}
-The old ones are the best: this is the good old \q{\i{15-puzzle}} with
-sliding tiles. You have a 4x4 square grid; 15 squares contain numbered
-tiles, and the sixteenth is empty. Your move is to choose a tile next
-to the empty space, and slide it into the space. The aim is to end up
-with the tiles in numerical order, with the space in the bottom right
-(so that the top row reads 1,2,3,4 and the bottom row reads
-13,14,15,\e{space}).
+The old ones are the best: this is the good old \q{\i{15-puzzle}}
+with sliding tiles. You have a 4\by\.4 square grid; 15 squares
+contain numbered tiles, and the sixteenth is empty. Your move is to
+choose a tile next to the empty space, and slide it into the space.
+The aim is to end up with the tiles in numerical order, with the
+space in the bottom right (so that the top row reads 1,2,3,4 and the
+bottom row reads 13,14,15,\e{space}).
\H{fifteen-controls} \i{Fifteen controls}
\H{sixteen-params} \I{parameters, for Sixteen}Sixteen parameters
-The only parameters available from the \q{Custom...} option on the
-\q{Type} menu are \e{Width} and \e{Height}, which are
-self-explanatory.
+The parameters available from the \q{Custom...} option on the
+\q{Type} menu are:
+
+\b \e{Width} and \e{Height}, which are self-explanatory.
+
+\b You can ask for a limited shuffling operation to be performed on
+the grid. By default, Sixteen will shuffle the grid in such a way
+that any arrangement is about as probable as any other. You can
+override this by requesting a precise number of shuffling moves to
+be performed. Typically your aim is then to determine the precise
+set of shuffling moves and invert them exactly, so that you answer
+(say) a four-move shuffle with a four-move solution. Note that the
+more moves you ask for, the more likely it is that solutions shorter
+than the target length will turn out to be possible.
+
+
+\C{twiddle} \i{Twiddle}
+
+\cfg{winhelp-topic}{games.twiddle}
+
+Twiddle is a tile-rearrangement puzzle, visually similar to Sixteen
+(see \k{sixteen}): you are given a grid of square tiles, each
+containing a number, and your aim is to arrange the numbers into
+ascending order.
+
+In basic Twiddle, your move is to rotate a square group of four
+tiles about their common centre. (Orientation is not significant in
+the basic puzzle, although you can select it.) On more advanced
+settings, you can rotate a larger square group of tiles.
+
+I first saw this type of puzzle in the GameCube game \q{Metroid
+Prime 2}. In the Main Gyro Chamber in that game, there is a puzzle
+you solve to unlock a door, which is a special case of Twiddle. I
+developed this game as a generalisation of that puzzle.
+
+\H{twiddle-controls} \I{controls, for Twiddle}Twiddle controls
+
+To play Twiddle, click the mouse in the centre of the square group
+you wish to rotate. In the basic mode, you rotate a 2\by\.2 square,
+which means you have to click at a corner point where four tiles
+meet.
+
+In more advanced modes you might be rotating 3\by\.3 or even more at
+a time; if the size of the square is odd then you simply click in
+the centre tile of the square you want to rotate.
+
+Clicking with the left mouse button rotates the group anticlockwise.
+Clicking with the right button rotates it clockwise.
+
+(All the actions described in \k{common-actions} are also available.)
+
+\H{twiddle-parameters} \I{parameters, for Twiddle}Twiddle parameters
+
+Twiddle provides several configuration options via the \q{Custom}
+option on the \q{Type} menu:
+
+\b You can configure the width and height of the puzzle grid.
+
+\b You can configure the size of square block that rotates at a time.
+
+\b You can ask for every square in the grid to be distinguishable
+(the default), or you can ask for a simplified puzzle in which there
+are groups of identical numbers. In the simplified puzzle your aim
+is just to arrange all the 1s into the first row, all the 2s into
+the second row, and so on.
+
+\b You can configure whether the orientation of tiles matters. If
+you ask for an orientable puzzle, each tile will have a triangle
+drawn in it. All the triangles must be pointing upwards to complete
+the puzzle.
+
+\b You can ask for a limited shuffling operation to be performed on
+the grid. By default, Twiddle will shuffle the grid so much that any
+arrangement is about as probable as any other. You can override this
+by requesting a precise number of shuffling moves to be performed.
+Typically your aim is then to determine the precise set of shuffling
+moves and invert them exactly, so that you answer (say) a four-move
+shuffle with a four-move solution. Note that the more moves you ask
+for, the more likely it is that solutions shorter than the target
+length will turn out to be possible.
\C{rectangles} \i{Rectangles}
number written in its numbered square.
Credit for this game goes to the Japanese puzzle magazine \i{Nikoli}
-\k{nikoli}; I've also seen a Palm implementation at \i{Puzzle Palace}
-\k{puzzle-palace}. Unlike Puzzle Palace's implementation, my version
-automatically generates random grids of any size you like. The quality
-of puzzle design is therefore not quite as good as hand-crafted
-puzzles would be (in particular, a unique solution cannot be
-guaranteed), but on the plus side you get an inexhaustible supply of
-puzzles tailored to your own specification.
+\k{nikoli-rect}; I've also seen a Palm implementation at \i{Puzzle
+Palace} \k{puzzle-palace-rect}. Unlike Puzzle Palace's
+implementation, my version automatically generates random grids of
+any size you like. The quality of puzzle design is therefore not
+quite as good as hand-crafted puzzles would be, but on the plus side
+you get an inexhaustible supply of puzzles tailored to your own
+specification.
-\B{nikoli} \W{http://www.nikoli.co.jp/puzzles/7/index_text-e.htm}\cw{http://www.nikoli.co.jp/puzzles/7/index_text-e.htm}
+\B{nikoli-rect} \W{http://www.nikoli.co.jp/puzzles/7/index_text-e.htm}\cw{http://www.nikoli.co.jp/puzzles/7/index_text-e.htm}
-\B{puzzle-palace} \W{http://www.puzzle.gr.jp/puzzle/sikaku/palm/index.html.en}\cw{http://www.puzzle.gr.jp/puzzle/sikaku/palm/index.html.en}
+\B{puzzle-palace-rect} \W{http://www.puzzle.gr.jp/puzzle/sikaku/palm/index.html.en}\cw{http://www.puzzle.gr.jp/puzzle/sikaku/palm/index.html.en}
\H{rectangles-controls} \I{controls, for Rectangles}Rectangles controls
\H{rectangles-params} \I{parameters, for Rectangles}Rectangles parameters
-The \q{Custom...} option on the \q{Type} menu offers you \e{Width}
-and \e{Height} parameters, which are self-explanatory.
+These parameters are available from the \q{Custom...} option on the
+\q{Type} menu.
+
+\dt \e{Width}, \e{Height}
+
+\dd Size of grid, in squares.
+
+\dt \e{Expansion factor}
-\q{Expansion factor} is a mechanism for changing the type of grids
-generated by the program. Some people prefer a grid containing a few
-large rectangles to one containing many small ones. So you can ask
+\dd This is a mechanism for changing the type of grids generated by
+the program. Some people prefer a grid containing a few large
+rectangles to one containing many small ones. So you can ask
Rectangles to essentially generate a \e{smaller} grid than the size
you specified, and then to expand it by adding rows and columns.
+\lcont{
+
The default expansion factor of zero means that Rectangles will
simply generate a grid of the size you ask for, and do nothing
further. If you set an expansion factor of (say) 0.5, it means that
though, the game simply cannot generate more than a few rectangles
to cover the entire grid, and the game becomes trivial.
-\H{rectangles-cmdline} \I{command line, for Rectangles}Additional
-command-line configuration
-
-The expansion factor parameter, described in \k{rectangles-params},
-is not mentioned by default in the game ID (see \k{common-id}). So
-if you set your expansion factor to (say) 0.75, and then you
-generate an 11x11 grid, then the game ID will simply say
-\c{11x11:}\e{numbers}. This means that if you send the game ID to
-another player and they paste it into their copy of Rectangles,
-their game will not be automatically configured to use the same
-expansion factor in any subsequent grids it generates. (I don't
-think the average person examining a single grid sent to them by
-another player would want their configuration modified to that
-extent.)
-
-If you are specifying a game ID or game parameters on the command
-line (see \k{common-cmdline}) and you do want to configure the
-expansion factor, you can do it by suffixing the letter \cq{e} to
-the parameters, followed by the expansion factor as a decimal
-number. For example:
-
-\b \cq{rect 11x11e0.75} starts Rectangles with a grid size of
-11\u00d7{x}11 and an expansion factor of 0.75.
-
-\b \cq{rect 11x11e0.75:g11c6e5e4a2_4e9c3b3d3b5g2b6c4k4g30a8n3j1g6a2}
-starts Rectangles with a grid size of 11\u00d7{x}11, an expansion
-factor of 0.75, \e{and} a specific game selected.
+}
+
+\dt \e{Ensure unique solution}
+
+\dd Normally, Rectangles will make sure that the puzzles it presents
+have only one solution. Puzzles with ambiguous sections can be more
+difficult and more subtle, so if you like you can turn off this
+feature and risk having ambiguous puzzles. Also, finding \e{all} the
+possible solutions can be an additional challenge for an advanced
+player. Turning off this option can also speed up puzzle generation.
+
\C{netslide} \i{Netslide}
\cfg{winhelp-topic}{games.netslide}
-This game was submitted by Richard Boulton. It combines the grid
-generation of Net (see \k{net}) with the movement of Sixteen (see
-\k{sixteen}): you have a Net grid, but instead of rotating tiles back
-into place you have to slide them into place by moving a whole row at
-a time.
+This game combines the grid generation of Net (see \k{net}) with the
+movement of Sixteen (see \k{sixteen}): you have a Net grid, but
+instead of rotating tiles back into place you have to slide them
+into place by moving a whole row at a time.
As in Sixteen, \I{controls, for Netslide}control is with the mouse.
See \k{sixteen-controls}.
-\I{parameters, for Netslide}Game parameters are the same as for Net
-(see \k{net-params}).
+\I{parameters, for Netslide}The available game parameters have similar
+meanings to those in Net (see \k{net-params}) and Sixteen (see
+\k{sixteen-params}).
+
+Netslide was contributed to this collection by Richard Boulton.
\C{pattern} \i{Pattern}
The only options available from the \q{Custom...} option on the \q{Type}
menu are \e{Width} and \e{Height}, which are self-explanatory.
+
+\C{solo} \i{Solo}
+
+\cfg{winhelp-topic}{games.solo}
+
+You have a square grid, which is divided into square or rectangular
+blocks. Each square must be filled in with a digit from 1 to the
+size of the grid, in such a way that
+
+\b every row contains only one occurrence of each digit
+
+\b every column contains only one occurrence of each digit
+
+\b every block contains only one occurrence of each digit.
+
+You are given some of the numbers as clues; your aim is to place the
+rest of the numbers correctly.
+
+The default puzzle size is 3\by\.3 (a 9\by\.9 actual grid, divided
+into nine 3\by\.3 blocks). You can also select sizes with
+rectangular blocks instead of square ones, such as 2\by\.3 (a
+6\by\.6 grid divided into six 3\by\.2 blocks).
+
+If you select a puzzle size which requires more than 9 digits, the
+additional digits will be letters of the alphabet. For example, if
+you select 3\by\.4 then the digits which go in your grid will be 1
+to 9, plus \cq{a}, \cq{b} and \cq{c}.
+
+I first saw this puzzle in \i{Nikoli} \k{nikoli-solo}, although it's also
+been popularised by various newspapers under the name \q{Sudoku} or
+\q{Su Doku}.
+
+\B{nikoli-solo} \W{http://www.nikoli.co.jp/puzzles/1/index_text-e.htm}\cw{http://www.nikoli.co.jp/puzzles/1/index_text-e.htm}
+
+\H{solo-controls} \I{controls, for Solo}Solo controls
+
+To play Solo, simply click the mouse in any empty square and then
+type a digit or letter on the keyboard to fill that square. If you
+make a mistake, click the mouse in the incorrect square and press
+Space to clear it again (or use the Undo feature).
+
+If you \e{right}-click in a square and then type a number, that
+number will be entered in the square as a \q{pencil mark}. You can
+have pencil marks for multiple numbers in the same square.
+
+The game pays no attention to pencil marks, so exactly what you use
+them for is up to you: you can use them as reminders that a
+particular square needs to be re-examined once you know more about a
+particular number, or you can use them as lists of the possible
+numbers in a given square, or anything else you feel like.
+
+To erase a single pencil mark, right-click in the square and type
+the same number again.
+
+All pencil marks in a square are erased when you left-click and type
+a number, or when you left-click and press space. Right-clicking and
+pressing space will also erase pencil marks.
+
+(All the actions described in \k{common-actions} are also available.)
+
+\H{solo-parameters} \I{parameters, for Solo}Solo parameters
+
+Solo allows you to configure two separate dimensions of the puzzle
+grid on the \q{Type} menu: the number of columns, and the number of
+rows, into which the main grid is divided. (The size of a block is
+the inverse of this: for example, if you select 2 columns and 3 rows,
+each actual block will have 3 columns and 2 rows.)
+
+You can also configure the type of symmetry shown in the generated
+puzzles. More symmetry makes the puzzles look prettier but may also
+make them easier, since the symmetry constraints can force more
+clues than necessary to be present. Completely asymmetric puzzles
+have the freedom to contain as few clues as possible.
+
+Finally, you can configure the difficulty of the generated puzzles.
+Difficulty levels are judged by the complexity of the techniques of
+deduction required to solve the puzzle: each level requires a mode
+of reasoning which was not necessary in the previous one. In
+particular, on difficulty levels \q{Trivial} and \q{Basic} there
+will be a square you can fill in with a single number at all times,
+whereas at \q{Intermediate} level and beyond you will have to make
+partial deductions about the \e{set} of squares a number could be in
+(or the set of numbers that could be in a square). At
+\q{Unreasonable} level, even this is not enough, and you will
+eventually have to make a guess, and then backtrack if it turns out
+to be wrong.
+
+Generating difficult puzzles is itself difficult: if you select
+\q{Intermediate} or \q{Advanced} difficulty, Solo may have to make
+many attempts at generating a puzzle before it finds one hard enough
+for you. Be prepared to wait, especially if you have also configured
+a large puzzle size.
+
+
+\C{mines} \i{Mines}
+
+\cfg{winhelp-topic}{games.mines}
+
+You have a grid of covered squares, some of which contain mines, but
+you don't know which. Your job is to uncover every square which does
+\e{not} contain a mine. If you uncover a square containing a mine,
+you lose. If you uncover a square which does not contain a mine, you
+are told how many mines are contained within the eight surrounding
+squares.
+
+This game needs no introduction; popularised by Windows, it is
+perhaps the single best known desktop puzzle game in existence.
+
+This version of it has an unusual property. By default, it will
+generate its mine positions in such a way as to ensure that you
+never need to \e{guess} where a mine is: you will always be able to
+deduce it somehow. So you will never, as can happen in other
+versions, get to the last four squares and discover that there are
+two mines left but you have no way of knowing for sure where they
+are.
+
+\H{mines-controls} \I{controls, for Mines}Mines controls
+
+This game is played with the mouse.
+
+If you left-click in a covered square, it will be uncovered.
+
+If you right-click in a covered square, it will place a flag which
+indicates that the square is believed to be a mine. Left-clicking in
+a marked square will not uncover it, for safety. You can right-click
+again to remove a mark placed in error.
+
+If you left-click in an \e{uncovered} square, it will \q{clear
+around} the square. This means: if the square has exactly as many
+flags surrounding it as it should have mines, then all the covered
+squares next to it which are \e{not} flagged will be uncovered. So
+once you think you know the location of all the mines around a
+square, you can use this function as a shortcut to avoid having to
+click on each of the remaining squares one by one.
+
+If you uncover a square which has \e{no} mines in the surrounding
+eight squares, then it is obviously safe to uncover those squares in
+turn, and so on if any of them also has no surrounding mines. This
+will be done for you automatically; so sometimes when you uncover a
+square, a whole new area will open up to be explored.
+
+All the actions described in \k{common-actions} are also available.
+
+Even Undo is available, although you might consider it cheating to
+use it. If you step on a mine, the program will only reveal the mine
+in question (unlike most other implementations, which reveal all of
+them). You can then Undo your fatal move and continue playing if you
+like. The program will track the number of times you died (and Undo
+will not reduce that counter), so when you get to the end of the
+game you know whether or not you did it without making any errors.
+
+(If you really want to know the full layout of the grid, which other
+implementations will show you after you die, you can always use the
+Solve menu option.)
+
+\H{mines-parameters} \I{parameters, for Mines}Mines parameters
+
+The options available from the \q{Custom...} option on the \q{Type}
+menu are:
+
+\dt \e{Width}, \e{Height}
+
+\dd Size of grid in squares.
+
+\dt \e{Mines}
+
+\dd Number of mines in the grid. You can enter this as an absolute
+mine count, or alternatively you can put a \cw{%} sign on the end in
+which case the game will arrange for that proportion of the squares
+in the grid to be mines.
+
+\lcont{
+
+Beware of setting the mine count too high. At very high densities,
+the program may spend forever searching for a solvable grid.
+
+}
+
+\dt \e{Ensure solubility}
+
+\dd When this option is enabled (as it is by default), Mines will
+ensure that the entire grid can be fully deduced starting from the
+initial open space. If you prefer the riskier grids generated by
+other implementations, you can switch off this option.
+
+
+\C{samegame} \i{Same Game}
+
+\cfg{winhelp-topic}{games.samegame}
+
+You have a grid of coloured squares, which you have to clear by
+highlighting contiguous regions of more than one coloured square;
+the larger the region you highlight, the more points you get (and
+the faster you clear the arena).
+
+If you clear the grid you win. If you end up with nothing but
+single squares (i.e., there are no more clickable regions left) you
+lose.
+
+Removing a region causes the rest of the grid to shuffle up:
+blocks that are suspended will fall down (first), and then empty
+columns are filled from the right.
+
+Same Game was contributed to this collection by James Harvey.
+
+\H{samegame-controls} \i{Same Game controls}
+
+\IM{Same Game controls} controls, for Same Game
+\IM{Same Game controls} keys, for Same Game
+\IM{Same Game controls} shortcuts (keyboard), for Same Game
+
+This game can be played with either the keyboard or the mouse.
+
+If you left-click an unselected region, it becomes selected (possibly
+clearing the current selection).
+
+If you left-click the selected region, it will be removed (and the
+rest of the grid shuffled immediately).
+
+If you right-click the selected region, it will be unselected.
+
+The cursor keys move a cursor around the grid. Pressing the Space or
+Enter keys while the cursor is in an unselected region selects it;
+pressing Space or Enter again removes it as above.
+
+\H{samegame-parameters} \I{parameters, for Same Game}Same Game parameters
+
+These parameters are available from the \q{Custom...} option on the
+\q{Type} menu.
+
+\dt \e{Width}, \e{Height}
+
+\dd Size of grid in squares.
+
+\dt \e{No. of colours}
+
+\dd Number of different colours used to fill the grid; the more colours,
+the fewer large regions of colour and thus the more difficult it is to
+successfully clear the grid.
+
+\dt \e{Scoring system}
+
+\dd Controls the precise mechanism used for scoring. With the default
+system, \q{(n-2)^2}, only regions of three squares or more will score
+any points at all. With the alternative \q{(n-1)^2} system, regions of
+two squares score a point each, and larger regions score relatively
+more points.
+
+\dt \e{Ensure solubility}
+
+\dd If this option is ticked (the default state), generated grids
+will be guaranteed to have at least one solution.
+
+\lcont{
+
+If you turn it off, the game generator will not try to guarantee
+soluble grids; it will, however, still ensure that there are at
+least 2 squares of each colour on the grid at the start (since a
+grid with exactly one square of a given colour is \e{definitely}
+insoluble). Grids generated with this option disabled may contain
+more large areas of contiguous colour, leading to opportunities for
+higher scores; they can also take less time to generate.
+
+}
+
+
+\C{flip} \i{Flip}
+
+\cfg{winhelp-topic}{games.flip}
+
+You have a grid of squares, some light and some dark. Your aim is to
+light all the squares up at the same time. You can choose any square
+and flip its state from light to dark or dark to light, but when you
+do so, other squares around it change state as well.
+
+Each square contains a small diagram showing which other squares
+change when you flip it.
+
+\H{flip-controls} \i{Flip controls}
+
+\IM{Flip controls} controls, for Flip
+\IM{Flip controls} keys, for Flip
+\IM{Flip controls} shortcuts (keyboard), for Flip
+
+This game can be played with either the keyboard or the mouse.
+
+Left-click in a square to flip it and its associated squares, or
+use the cursor keys to choose a square and the space bar or Enter
+key to flip.
+
+If you use the \q{Solve} function on this game, it will mark some of
+the squares in red. If you click once in every square with a red
+mark, the game should be solved. (If you click in a square
+\e{without} a red mark, a red mark will appear in it to indicate
+that you will need to reverse that operation to reach the solution.)
+
+\H{flip-parameters} \I{parameters, for flip}Flip parameters
+
+These parameters are available from the \q{Custom...} option on the
+\q{Type} menu.
+
+\dt \e{Width}, \e{Height}
+
+\dd Size of grid in squares.
+
+\dt \e{Shape type}
+
+\dd This control determines the shape of the region which is flipped
+by clicking in any given square. The default setting, \q{Crosses},
+causes every square to flip itself and its four immediate neighbours
+(or three or two if it's at an edge or corner). The other setting,
+\q{Random}, causes a random shape to be chosen for every square, so
+the game is different every time.
+
+
+\C{guess} \i{Guess}
+
+\cfg{winhelp-topic}{games.guess}
+
+You have a set of coloured pegs, and have to reproduce a
+predetermined sequence of them (chosen by the computer) within a
+certain number of guesses.
+
+Each guess gets marked with the number of correctly-coloured pegs
+in the correct places (in black), and also the number of
+correctly-coloured pegs in the wrong places (in white).
+
+This game is also known (and marketed, by Hasbro, mainly) as
+a board game \q{Mastermind}, with 6 colours, 4 pegs per row, and 10 guesses.
+However, this version allows custom settings of number of colours
+(up to 10), number of pegs per row, and number of guesses.
+
+Guess was contributed to this collection by James Harvey.
+
+\H{guess-controls} \i{Guess controls}
+
+\IM{Guess controls} controls, for Guess
+\IM{Guess controls} keys, for Guess
+\IM{Guess controls} shortcuts (keyboard), for Guess
+
+This game can be played with either the keyboard or the mouse.
+
+With the mouse, drag a coloured peg from the tray on the left-hand
+side to its required position in the current guess; pegs may also be
+dragged from current and past guesses to copy them elsewhere. To
+remove a peg, drag it off its current position to somewhere invalid.
+
+Right-clicking in the current guess adds a \q{hold} marker; pegs
+that have hold markers will be automatically added to the next guess
+after marking.
+
+Alternatively, with the keyboard, the up and down cursor keys can be
+used to select a peg colour, the left and right keys to select a
+peg position, and the space bar or Enter key to place a peg of the
+selected colour in the chosen position. \q{D} or Backspace removes a
+peg, and \q{H} adds a hold marker.
+
+When the guess is complete, the smaller feedback pegs will be highlighted;
+clicking on these (or moving the peg cursor to them with the arrow keys
+and pressing the space bar or Enter key) will mark the current guess,
+copy any held pegs to the next guess, and move the \q{current guess}
+marker.
+
+If you correctly position all the pegs the solution will be displayed
+below; if you run out of guesses (or select \q{Solve...}) the solution
+will also be revealed.
+
+\H{guess-parameters} \I{parameters, for Guess}Guess parameters
+
+These parameters are available from the \q{Custom...} option on the
+\q{Type} menu. The default game matches the parameters for the
+board game \q{Mastermind}.
+
+\dt \e{Colours}
+
+\dd Number of colours the solution is chosen from; from 2 to 10
+(more is harder).
+
+\dt \e{Pegs per guess}
+
+\dd Number of pegs per guess (more is harder).
+
+\dt \e{Guesses}
+
+\dd Number of guesses you have to find the solution in (fewer is harder).
+
+\dt \e{Allow blanks}
+
+\dd Allows blank pegs to be given as part of a guess (makes it easier, because
+you know that those will never be counted as part of the solution). This
+is turned off by default.
+
+Note that this doesn't allow blank pegs in the solution; if you really wanted
+that, use one extra colour.
+
+\dt \e{Allow duplicates}
+
+\dd Allows the solution (and the guesses) to contain colours more than once;
+this increases the search space (making things harder), and is turned on by
+default.
+
+
+\C{pegs} \i{Pegs}
+
+\cfg{winhelp-topic}{games.pegs}
+
+A number of pegs are placed in holes on a board. You can remove a
+peg by jumping an adjacent peg over it (horizontally or vertically)
+to a vacant hole on the other side. Your aim is to remove all but one
+of the pegs initially present.
+
+This game, best known as \q{Peg Solitaire}, is possibly one of the
+oldest puzzle games still commonly known.
+
+\H{pegs-controls} \i{Pegs controls}
+
+\IM{Pegs controls} controls, for Pegs
+
+To move a peg, drag it with the mouse from its current position to
+its final position. If the final position is exactly two holes away
+from the initial position, is currently unoccupied by a peg, and
+there is a peg in the intervening square, the move will be permitted
+and the intervening peg will be removed.
+
+Vacant spaces which you can move a peg into are marked with holes. A
+space with no peg and no hole is not available for moving at all: it
+is an obstacle which you must work around.
+
+
+\H{pegs-parameters} \I{parameters, for Pegs}Pegs parameters
+
+These parameters are available from the \q{Custom...} option on the
+\q{Type} menu.
+
+\dt \e{Width}, \e{Height}
+
+\dd Size of grid in holes.
+
+\dt \e{Board type}
+
+\dd Controls whether you are given a board of a standard shape or a
+randomly generated shape. The two standard shapes currently
+supported are \q{Cross} and \q{Octagon} (also commonly known as the
+English and European traditional board layouts respectively).
+Selecting \q{Random} will give you a different board shape every
+time (but always one that is known to have a solution).
+
+
+\C{dominosa} \i{Dominosa}
+
+\cfg{winhelp-topic}{games.dominosa}
+
+A normal set of dominoes \dash that is, one instance of every
+(unordered) pair of numbers from 0 to 6 \dash has been arranged
+irregularly into a rectangle; then the number in each square has
+been written down and the dominoes themselves removed. Your task is
+to reconstruct the pattern by arranging the set of dominoes to match
+the provided array of numbers.
+
+This puzzle is widely credited to O. S. Adler, and takes part of its
+name from those initials.
+
+\H{dominosa-controls} \i{Dominosa controls}
+
+\IM{Dominosa controls} controls, for Dominosa
+
+Left-clicking between any two adjacent numbers places a domino
+covering them, or removes one if it is already present. Trying to
+place a domino which overlaps existing dominoes will remove the ones
+it overlaps.
+
+Right-clicking between two adjacent numbers draws a line between
+them, which you can use to remind yourself that you know those two
+numbers are \e{not} covered by a single domino. Right-clicking again
+removes the line.
+
+
+\H{dominosa-parameters} \I{parameters, for Dominosa}Dominosa parameters
+
+These parameters are available from the \q{Custom...} option on the
+\q{Type} menu.
+
+\dt \e{Maximum number on dominoes}
+
+\dd Controls the size of the puzzle, by controlling the size of the
+set of dominoes used to make it. Dominoes with numbers going up to N
+will give rise to an (N+2) \by (N+1) rectangle; so, in particular,
+the default value of 6 gives an 8\by\.7 grid.
+
+\dt \e{Ensure unique solution}
+
+\dd Normally, Dominosa will make sure that the puzzles it presents
+have only one solution. Puzzles with ambiguous sections can be more
+difficult and sometimes more subtle, so if you like you can turn off
+this feature. Also, finding \e{all} the possible solutions can be an
+additional challenge for an advanced player. Turning off this option
+can also speed up puzzle generation.
+
+
+\C{untangle} \i{Untangle}
+
+\cfg{winhelp-topic}{games.untangle}
+
+You are given a number of points, some of which have lines drawn
+between them. You can move the points about arbitrarily; your aim is
+to position the points so that no line crosses another.
+
+I originally saw this in the form of a Flash game called \i{Planarity}
+\k{Planarity}, written by John Tantalo.
+
+\B{Planarity} \W{http://home.cwru.edu/~jnt5/Planarity}\cw{http://home.cwru.edu/~jnt5/Planarity}
+
+\H{untangle-controls} \i{Untangle controls}
+
+\IM{Untangle controls} controls, for Untangle
+
+To move a point, click on it with the left mouse button and drag it
+into a new position.
+
+\H{untangle-parameters} \I{parameters, for Untangle}Untangle parameters
+
+There is only one parameter available from the \q{Custom...} option
+on the \q{Type} menu:
+
+\dt \e{Number of points}
+
+\dd Controls the size of the puzzle, by specifying the number of
+points in the generated graph.
+
+
+\C{blackbox} \i{Black Box}
+
+\cfg{winhelp-topic}{games.blackbox}
+
+A number of balls are hidden in a rectangular arena. You have to
+deduce the positions of the balls by firing lasers from positions
+on the edge of the arena and observing how they are deflected.
+
+Lasers will fire straight until they hit the opposite side of the
+arena (at which point they emerge), unless affected by balls in one of
+the following ways:
+
+\b A laser that hits a ball head-on is absorbed and will never re-emerge.
+ This includes lasers that meet a ball on the first rank of the arena.
+
+\b A laser with a ball to its front-left square gets deflected 90 degrees
+ to the right.
+
+\b A laser with a ball to its front-right square gets similarly deflected
+ to the left.
+
+\b A laser that would re-emerge from the entry location is considered to be
+ \q{reflected}.
+
+\b A laser which would get deflected before entering the arena (down the
+ \q{firing range}) by a ball to the front-left or front-right of its
+ entry point is also considered to be \q{reflected}.
+
+Lasers that are reflected appear as a \q{R}; lasers that hit balls
+dead-on appear as \q{H}. Otherwise, a number appears at the firing point
+and the location where the laser emerges (this number is unique to
+that shot).
+
+You can place guesses as to the location of the balls, based on the
+entry and exit patterns of the lasers; once you have placed enough
+balls a button appears enabling you to have your guesses checked.
+
+Here is a diagram showing how the positions of balls can create each
+of the laser behaviours shown above:
+
+\c 1RHR----
+\c |..O.O...|
+\c 2........3
+\c |........|
+\c |........|
+\c 3........|
+\c |......O.|
+\c H........|
+\c |.....O..|
+\c 12-RH---
+
+As shown, it is possible for a ball to receive multiple reflections
+before re-emerging (see turn 3). Similarly, a ball may be reflected
+(possibly more than once) before receiving a hit (the \q{H} on the
+left side of the example).
+
+Note that any layout with more that 4 balls may have a non-unique
+solution. The following diagram illustrates this; if you know the
+board contains 5 balls, it is impossible to determine where the fifth
+ball is (possible positions marked with an x):
+
+\c --------
+\c |........|
+\c |........|
+\c |..O..O..|
+\c |...xx...|
+\c |...xx...|
+\c |..O..O..|
+\c |........|
+\c |........|
+\c --------
+
+For this reason when you have your guesses checked the game will
+check that your solution \e{produces the same results} as the
+computer's, rather than that your solution is identical to the
+computer's. So in the above example, you could put the fifth ball at
+\e{any} of the locations marked with an x, and you would still win.
+
+Black Box was contributed to this collection by James Harvey.
+
+\H{blackbox-controls} \i{Black Box controls}
+
+\IM{Black Box controls}controls, for Black Box
+
+To fire a laser, left-click in a square around the side of the arena.
+The results will be displayed immediately. Lasers may not be fired
+twice (because the results will never change). Holding down the left
+button will highlight the current go (or a previous go) to confirm the
+exit point for that laser, if applicable.
+
+To guess the location of a ball, left-click within the arena and a
+black circle will appear marking the guess; to remove the guessed ball
+click again.
+
+Locations in the arena may be locked against modification by
+right-clicking; whole rows and columns may be similarly locked by
+right-clicking in the laser firing range above/below that column, or
+to the left/right of that row.
+
+When an appropriate number of balls have been guessed a button will
+appear at the top-left corner of the grid; clicking that will mark
+your guesses.
+
+If you click the \q{mark} button and your guesses are not correct,
+the game will show you as little information as possible to
+demonstrate this to you, so you can try again. If your ball
+positions are not consistent with the laser paths you already know
+about, one laser path will be circled to indicate that it proves you
+wrong. If your positions match all the existing laser paths but are
+still wrong, one new laser path will be revealed (written in red)
+which is not consistent with your current guesses.
+
+If you decide to give up completely, you can select Solve to reveal
+the actual ball positions. At this point, correctly-placed balls
+will be displayed as filled black circles; incorrectly-placed balls
+are displayed as filled black circles with red crosses, and missing
+balls are filled red circles. In addition, a red circle marks any
+laser you had already fired which is not consistent with your ball
+layout (just as when you press the mark button), and red text marks
+any laser you \e{could} have fired in order to distinguish your ball
+layout from the right one.
+
+(All the actions described in \k{common-actions} are also available.)
+
+\H{blackbox-parameters} \I{parameters, for Black Box}Black Box parameters
+
+These parameters are available from the \q{Custom...} option on the
+\q{Type} menu.
+
+\dt \e{Width}, \e{Height}
+
+\dd Size of grid in squares. There are 2 \by \e{Width} \by \e{Height} lasers
+per grid, two per row and two per column.
+
+\dt \e{No. of balls}
+
+\dd Number of balls to place in the grid. This can be a single number,
+or a range (separated with a hyphen, like \q{2-6}), and determines the
+number of balls to place on the grid. The \q{reveal} button is only
+enabled if you have guessed an appropriate number of balls; a guess
+using a different number to the original solution is still acceptable,
+if all the laser inputs and outputs match.
+
+
+\C{slant} \i{Slant}
+
+\cfg{winhelp-topic}{games.slant}
+
+You have a grid of squares. Your aim is to draw a diagonal line
+through each square, and choose which way each line slants so that
+the following conditions are met:
+
+\b The diagonal lines never form a loop.
+
+\b Any point with a circled number has precisely that many lines
+meeting at it. (Thus, a 4 is the centre of a cross shape, whereas a
+zero is the centre of a diamond shape \dash or rather, a partial
+diamond shape, because a zero can never appear in the middle of the
+grid because that would immediately cause a loop.)
+
+Credit for this puzzle goes to \i{Nikoli} \k{nikoli-slant}.
+
+\B{nikoli-slant}
+\W{http://www.nikoli.co.jp/puzzles/39/index.htm}\cw{http://www.nikoli.co.jp/puzzles/39/index.htm}
+(in Japanese)
+
+
+\H{slant-controls} \i{Slant controls}
+
+\IM{Slant controls} controls, for Slant
+\IM{Slant controls} keys, for Slant
+\IM{Slant controls} shortcuts (keyboard), for Slant
+
+Left-clicking in a blank square will place a \cw{\\} in it (a line
+leaning to the left, i.e. running from the top left of the square to
+the bottom right). Right-clicking in a blank square will place a
+\cw{/} in it (leaning to the right, running from top right to bottom
+left).
+
+Continuing to click either button will cycle between the three
+possible square contents. Thus, if you left-click repeatedly in a
+blank square it will change from blank to \cw{\\} to \cw{/} back to
+blank, and if you right-click repeatedly the square will change from
+blank to \cw{/} to \cw{\\} back to blank. (Therefore, you can play
+the game entirely with one button if you need to.)
+
+(All the actions described in \k{common-actions} are also available.)
+
+\H{slant-parameters} \I{parameters, for Slant}Slant parameters
+
+These parameters are available from the \q{Custom...} option on the
+\q{Type} menu.
+
+\dt \e{Width}, \e{Height}
+
+\dd Size of grid in squares.
+
+
+\C{lightup} \i{Light Up}
+
+\cfg{winhelp-topic}{games.lightup}
+
+You have a grid of squares. Some are filled in black; some of the
+black squares are numbered. Your aim is to \q{light up} all the
+empty squares by placing light bulbs in some of them.
+
+Each light bulb illuminates the square it is on, plus all squares in
+line with it horizontally or vertically unless a black square is
+blocking the way.
+
+To win the game, you must satisfy the following conditions:
+
+\b All non-black squares are lit.
+
+\b No light is lit by another light.
+
+\b All numbered black squares have exactly that number of lights adjacent to
+ them (in the four squares above, below, and to the side).
+
+Non-numbered black squares may have any number of lights adjacent to them.
+
+Credit for this puzzle goes to \i{Nikoli} \k{nikoli-lightup}.
+
+Light Up was contributed to this collection by James Harvey.
+
+\B{nikoli-lightup}
+\W{http://www.nikoli.co.jp/puzzles/32/index-e.htm}\cw{http://www.nikoli.co.jp/puzzles/32/index-e.htm}
+(beware of Flash)
+
+\H{lightup-controls} \i{Light Up controls}
+
+\IM{Light Up controls} controls, for Light Up
+\IM{Light Up controls} keys, for Light Up
+\IM{Light Up controls} shortcuts (keyboard), for Light Up
+
+Left-clicking in a non-black square will toggle the presence of a light
+in that square. Right-clicking in a non-black square toggles a mark there to aid
+solving; it can be used to highlight squares that cannot be lit, for example.
+
+You may not place a light in a marked square, nor place a mark in a lit square.
+
+The game will highlight obvious errors in red. Lights lit by other
+lights are highlighted in this way, as are numbered squares which
+do not (or cannot) have the right number of lights next to them.
+
+Thus, the grid is solved when all non-black squares have yellow
+highlights and there are no red lights.
+
+
+\H{lightup-parameters} \I{parameters, for Light Up}Light Up parameters
+
+These parameters are available from the \q{Custom...} option on the
+\q{Type} menu.
+
+\dt \e{Width}, \e{Height}
+
+\dd Size of grid in squares.
+
+\dt \e{%age of black squares}
+
+\dd Rough percentage of black squares in the grid.
+
+\lcont{
+
+This is a hint rather than an instruction. If the grid generator is
+unable to generate a puzzle to this precise specification, it will
+increase the proportion of black squares until it can.
+
+}
+
+\dt \e{Symmetry}
+
+\dd Allows you to specify the required symmetry of the black squares
+in the grid. (This does not affect the difficulty of the puzzles
+noticeably.)
+
+\dt \e{Difficulty}
+
+\dd \q{Easy} means that the puzzles should be soluble without
+backtracking or guessing, \q{Hard} means that some guesses will
+probably be necessary.
+
+
\A{licence} \I{MIT licence}\ii{Licence}
This software is \i{copyright} 2004-2005 Simon Tatham.
-Portions copyright Richard Boulton.
+Portions copyright Richard Boulton and James Harvey.
Permission is hereby granted, free of charge, to any person
obtaining a copy of this software and associated documentation files
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
-\IM{specific...} Specific..., menu option
-\IM{custom...} Custom..., menu option
+\IM{specific} \q{Specific}, menu option
+\IM{custom} \q{Custom}, menu option
\IM{game ID} game ID
\IM{game ID} ID, game
~mdw / sgt / puzzles / blobdiff