In Rainbow Stacker, you have to stack up as many of the brightly colored layers to build a high tower in all the colors of the rainbow. The layers shift color along a smooth gradient, making the game very soothing and pleasantly colorful. Try to halt the sliding layer at the right moment so that it is aligned exactly with the previous floor of the tower. If there is any overhang, the excess section of the layer will be chopped off. That means that with every slight miss, the surface you have left to build on will become slightly smaller. Keep playing until the very tiniest sliver misses the mark. What's the highest tower you can build?