Package enigma

Game where you control a marble with the mouse

http://www.nongnu.org/enigma/

Enigma is a tribute to and a re-implementation of one of the most
original and intriguing computer games of the 1990's: Oxyd. Your
objective is easily explained: find and uncover all pairs of identical
Oxyd stones in each landscape. Sounds simple? It would be, if it
weren't for hidden traps, vast mazes, insurmountable obstacles and
innumerable puzzles blocking your direct way to the Oxyd stones...

Games (Section 6)
enigma
The object of the game is to find and uncover pairs of identically colored Oxyd stones. Simple? Yes. Easy? Certainly not! Hidden traps, vast mazes, laser beams...