ref: 796e5e6000677a39577d545e4603ce251e7cbfe9
dir: /sys/src/games/sokoban/README/
If you click with mouse button 1 on a (destination) square then the following may happen. If - the destination square is on the same row or column as glenda, and - there is a ball next to glenda (in the direction of the destination square), and - all squares between the ball and the destination square (where glenda will move) are empty, and - the square next to the destination square where glenda will push the ball is empty too, then glenda will move to the destination square, pushing the ball while moving. Otherwise, if glenda can go to the destination square without touching anything, it will do so. Otherwise, nothing will happen. The breadth-first search algorithm should find a fast route. it can be seen in action by toggling the 'animate' entry in the button 3 menu.