The Ishango bone is a bone with notches that some say contains the first known table of prime numbers. This puzzle is inspired by this story. Cubes containing prime numbers fall onto the board and you are challenged to get the sum of 11. This sum equals ISHANGO. In each level you have a time limit to complete the mission of collecting Ishangos of different colors. The game gets more challenging with each level. This puzzle game mixes skill and strategy. It is a fun and intelligent game. Enjoy it.