The River Test is an iPhone app that's part game, part logic puzzle and a whole lot of fun. It's based on a Japanese IQ test that supposedly given to job candidates. It's believed that only 10% of the population can solve it without assistance.
The idea behind the puzzle game is straightforward- get eight people from one side of the river to the other using a raft. It sounds easy, but there are five rules governing the river crossing that make it a challenge. You have a Dad with his two sons, a Mom with her two daughters, a policeman and a criminal. Only 2 people can travel on the raft at a time. The Father cannot stay with any of the daughters, without their Mother's presence. The Mother cannot stay with any of the sons, without their Father's presence. The criminal cannot stay with any family member if the policeman is not there. Only the father, mother and the policeman know how to operate the raft.
Once you have the rules down, you can start placing the appropriate people on the raft to carry them to the other side. There's a counter that tracks the number of moves and a timer to log how long it takes you to complete the game. The game prevents you from making a prohibited move (like leaving the criminal with the kids), but you have to figure out the solution by trial and error. If you can't solve the River Test, the game provides the answer.
It's a basic game with colorful graphics. The controls are responsive, and the game never crashed while I played. The graphics are not the focus of the game, though. Most of the fun is the challenge of the puzzle and seeing if you and your friends can solve it. I'm skeptical about the claim that only 10% can solve the river test, but that doesn't take away the challenge. Best of all, The River Test is a universal app and available for free from the App Store.