Water Sort Puzzle is a free, fun, and addictive game developed by Thu Dau. It is a brain training game that challenges you to sort watercolors in a tube until each tube is filled with water of the same color. The game is suitable for all ages and is available on iPhone.

The game is easy to play with only one finger. You can touch any tube to pour the top portion of water into another tube. However, you can only pour water into one tube if the water is of the same color and the tube has room to fill. If you get stuck, you can add one more tube to make it easier. The game offers unlimited time and levels, making it a perfect game to kill time and train your brain. Water Sort Puzzle is also playable in offline mode, so no network connection is required.