NIM(n) is played by two players, who alternate removing one or two stones from a heap of originally n stones. The player who cannot move anymore, since no stones are left, loses.
Move the mouse over the rightmost stone or over the stone next to that. Click on either to remove one or two stones. Then the next player moves and clicks. This game can be played with 5 to 10 stones initially.
Erich Prisner, 2012