X Labyrinth  is a  labyrinth  game   under X11 that is played
directly with the mouse  pointer: the  walls block the pointer's
movement on the screen.

   The goal of the game is to retrieve the four colored squares:
to retrieve a square, it is sufficient to move  the pointer over
it,  and  it  will  disappear.  However,  to  make  things  more
infuriating,  the  squares  have  to be  taken in the  following 
order:  red,  yellow,  green  and  blue. When the blue square is
obtained, the game is won.

WWW: http://www.eleves.ens.fr:8080/home/madore/programs/#prog_xlaby