This is a guessing and deduction game, you need to discover the hidden code by trial and error.
It is part of the javagames pack (see: http://javagames.sourceforge.net/) and you can download the stomak-1.0.jar containing both source code and compiled binary of this particular game.
About game
Computer makes random combination of 4 images which can be either of these:
Click at small images in fields to set the desired
combination and then click on to compare it with
combination that you need to guess.