\cfg{text-filename}{puzzles.txt}
-\cfg{xhtml-contents-filename}{index.html}
-\cfg{xhtml-leaf-level}{1}
-\cfg{xhtml-contents-depth-0}{1}
-\cfg{xhtml-contents-depth-1}{2}
-\cfg{xhtml-leaf-contains-contents}{true}
+\cfg{html-contents-filename}{index.html}
+\cfg{html-template-filename}{%k.html}
+\cfg{html-index-filename}{docindex.html}
+\cfg{html-leaf-level}{1}
+\cfg{html-contents-depth-0}{1}
+\cfg{html-contents-depth-1}{2}
+\cfg{html-leaf-contains-contents}{true}
\cfg{info-filename}{puzzles.info}
\cfg{ps-filename}{puzzles.ps}
\cfg{pdf-filename}{puzzles.pdf}
+\define{by} \u00D7{x}
+
This is a collection of small one-player puzzle games.
\copyright This manual is copyright 2004 Simon Tatham. All rights
reserved. You may distribute this documentation under the MIT licence.
See \k{licence} for the licence text in full.
-\versionid $Id$
+\cfg{html-local-head}{<meta name="AppleTitle" content="Puzzles Help">}
+\versionid $Id$
\C{intro} Introduction
I wrote this collection because I thought there should be more small
desktop toys available: little games you can pop up in a window and
play for two or three minutes while you take a break from whatever
-else you were doing. And I was also annoyed that every time I found a
-good game on (say) \i{Unix}, it wasn't available the next time I was
-sitting at a \i{Windows} machine, or vice versa; so I arranged that
-everything in my personal puzzle collection will happily run on both.
-When I 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 - Mac OS, PocketPC, or whatever it might be - then all the games
-in this framework will immediately become available on another
-platform as well.
+else you were doing. And I was also annoyed that every time I found
+a good game on (say) \i{Unix}, it wasn't available the next time I
+was sitting at a \i{Windows} machine, or vice versa; so I arranged
+that everything in my personal puzzle collection will happily run on
+both, and have more recently done a port to Mac OS X as well. When I
+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.
The actual games in this collection were mostly not my invention; I
saw them elsewhere, and rewrote them in a form that was more
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. Undo is lost.
+\dd Resets the current game to its initial state. (This can be undone.)
\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.
+
+\lcont{
-\H{common-id} Recreating games with the \ii{game ID}
+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 \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.
+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.
-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.
+}
-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.
+\dt \I{exit}\ii\e{Quit} (\q{Q}, Ctrl+\q{Q})
-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.
+\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}
+(This section does not apply to the Mac OS X version.)
+
The games in this collection deliberately do not ever save
information on to the computer they run on: they have no high score
tables and no saved preferences. (This is because I expect at least
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}
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}
\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}
\I{parameters, for Netslide}Game parameters are the same as for Net
(see \k{net-params}).
+
\C{pattern} \i{Pattern}
\cfg{winhelp-topic}{games.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).
+
+(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.
+
+
\A{licence} \I{MIT licence}\ii{Licence}
-This software is \i{copyright} 2004 Simon Tatham.
+This software is \i{copyright} 2004-2005 Simon Tatham.
Portions copyright Richard Boulton.
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