Gem'X is a 1991 puzzle game for the Commodore Amiga and C64 platforms and the Atari ST by the German company Kaiko. The player is presented with two rectangular grids of gems, the left one of which is changeable, and the right one is static. The object is to click on the gems on the left grid to make it look exactly like the right one. The challenge comes from the fact that changing a gem also causes the four gems adjacent to it to change.
Gem'X originally caused special interest because of the …