Su Docu (http://jcrossword.narod.ru/), written in OPL, is a version of the increasingly popular numbers puzzle game, So Doku, in which every 3 x 3 grid and every 9 long column and row must have the numbers 1 to 9 in it. You will need the OPL run time installed in order to use the game. Also by the same author is a version of Japanese Crossword and the Game of Life.

Screenshot from the Game of Life:

http://jcrossword.narod.ru/index_files/image004.jpg