You're presented with a set of bricks with colored orbs sparkling inside. Using the mouse, drag blocks left or right one at a time, keeping in mind that gravity tugs them down at the earliest possible chance. If two or more blocks of the same color touch, they smash and crumble away. The challenge comes from knowing when to keep blocks around to serve as place holders to slide stranded colors to their peers. It's extraordinarily perplexing at times, but that challenge is what makes it so fun.