There are two players, and each one gets 4 cards, a "4", a "3", a "2", a "1". Each player orders his or her four cards into a pile. Then repeatedly both players reveal their leftmost card. The lower card is taken away from the pile, thrown away, and the higher one, the winning one, remains in the pile. In case of identical cards, both cards are removed. There is also one exception: If one card is a "1" and the other a "4", then both cards are removed. The first player having an empty pile loses.
In this applet you can play against the computer (who plays optimally). Select your pile from left to right by clicking on the available cards. In the meantime, the computer will select its pile, but not reveal it to you yet. Of course the computer will make its choice without noticing your pile selection. Once you have chosen all four, the process starts automatically. Then lean back and observe. When the game is finished, you can play another one.
Erich Prisner, 2012