Candy (the straight tetromino shape) is falling to the right. When she gets to the center block, she can't go any farther and will freeze in place, completing the innermost red square.

The innermost red square has disappeared and the other squares have moved inward. A new shape (Tyrone) has appeared at the right of the grid and is falling to the left.

In higher levels, you must control 2, 3, or even 4 shapes at once! Here there are 3 shapes.

The game is over when there is no room for the next shape to appear at the edge of the grid. Shapes decide where they want to appear before checking whether that edge is clear, so the game may end before all four edges are blocked.