Want a deadly challenge? Try The Rock Game, a version of the ancient puzzle Nim. It appears to be very simple, but it can quickly reverse any advantage you may have and beat you repeatedly.The objective of this game is very simple: do NOT be the one to take the last rock. This can be very tricky and deceivingly hard. The rules are also very basic: you must take at least one rock every turn, and you may not take rocks from two separate rows in the same turn.Try not to get stuck between a rock and a hard spot and enjoy!