The New Tetris (1999)

There are several key differences in gameplay from the original Tetris. First, in addition to clearing lines, one can also form 4x4 large squares of four pieces to form blocks. When a block is created, it turns solid gold or silver, depending on the makeup of the block. Blocks can only be constructed from whole pieces: if any part of a piece has been cleared, then it cannot be used to form a block. When a line that has pieces from a block is cleared, it earns more points.