New puzzle: Dominosa.

[originally from svn r6091]

puzzles.but

@@ -1193,6 +1193,56 @@ 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 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.
+
+
 \A{licence} \I{MIT licence}\ii{Licence}
 
 This software is \i{copyright} 2004-2005 Simon Tatham.