Lumines resembles Tetris on first impression, and it's similarly intuitive to pick up and play--though, the simple design belies tremendous depth. Squares comprising four smaller blocks, which can be one of two colors, fall from the top of the screen. The object is to form solid-colored rectangles of at least two-by-two blocks by rotating and arranging the falling squares properly. Solid rectangles instantly light up and get cleared away as a line (called the "timeline") intermittently passes from left to right across the screen, kind of like a windshield wiper and just like a timeline in a music sequencer program.