O-Tetromino — The Square Piece

Color: Yellow

A 2×2 square piece. Its shape never changes when rotated, making it the easiest piece to handle.

The O-piece forms a square out of four cells, and its shape stays identical no matter which way you rotate it. Since you never have to think about rotation, it's the easiest piece for beginners to place.

But because it's square, it doesn't fit uneven surfaces well and can often leave gaps. It's ideal on a flat two-cell space and is best used to keep the stack surface level.

Since its width is fixed at two cells, it can't fit into a one-cell well, so when using a well strategy, save the O-piece for filling flat surfaces instead.