X-Git-Url: https://git.distorted.org.uk/~mdw/sgt/puzzles/blobdiff_plain/3101ae2613f66463bd4d3b1fe5a188df1aee3271..36d01ffa8154db198db95b4cc3f788a430c7fee2:/puzzles.but

diff --git a/puzzles.but b/puzzles.but
index 1e6c0fa..5f8bff4 100644
--- a/puzzles.but
+++ b/puzzles.but
@@ -415,9 +415,41 @@ Right-clicking will move it in the opposite direction.
 
 \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.
+
+\H{sixteen-cmdline} \I{command line, for Sixteen}Additional
+command-line configuration
+
+The limited shuffle parameter, described in \k{sixteen-params}, is
+not mentioned by default in the game ID (see \k{common-id}). So if
+you set your shuffling move count to (say) 4, and then you generate
+a normal 4\by\.4 grid, then the game ID will simply say
+\c{4x4:}\e{numbers}. This means that if you send the game ID to
+another player and they paste it into their copy of Sixteen, their
+game will not be automatically configured to use the same shuffle
+limit 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
+shuffle limit, you can do it by suffixing the letter \cq{m} to the
+parameters, followed by the move count as a decimal number. For
+example, \cq{sixteen 4x4m4} will start up Sixteen with a problem
+guaranteed to be soluble in four moves or fewer.
 
 
 \C{twiddle} \i{Twiddle}
@@ -475,6 +507,36 @@ 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.
+
+\H{twiddle-cmdline} \I{command line, for Twiddle}Additional
+command-line configuration
+
+The limited shuffle parameter, described in \k{twiddle-parameters},
+is not mentioned by default in the game ID (see \k{common-id}). So
+if you set your shuffling move count to (say) 4, and then you
+generate a normal 3\by\.3 grid, then the game ID will simply say
+\c{3x3n2:}\e{numbers}. This means that if you send the game ID to
+another player and they paste it into their copy of Twiddle, their
+game will not be automatically configured to use the same shuffle
+limit 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
+shuffle limit, you can do it by suffixing the letter \cq{m} to the
+parameters, followed by the move count as a decimal number. For
+example, \cq{twiddle 3x3n2m4} will start up Twiddle with a problem
+guaranteed to be soluble in four moves or fewer.
 
 \C{rectangles} \i{Rectangles}
 
@@ -691,9 +753,10 @@ 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). None of the
-difficulty levels generated by this program ever requires making a
-guess and backtracking if it turns out to be wrong.
+(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
@@ -738,6 +801,8 @@ parameters:
 
 \b \cq{da} for Advanced difficulty level
 
+\b \cq{du} for Unreasonable difficulty level
+
 So, for example, you can make Solo generate asymmetric 3x4 grids by
 running \cq{solo 3x4a}, or 4-way rotationally symmetric 2x3 grids by
 running \cq{solo 2x3r4}, or \q{Advanced}-level 2x3 grids by running