The New Tetris, Square mode of Tetris Worlds, and Lockjaw: The Overdose reward the player for creating 4x4 block squares out of four tetrominoes.
Building wide platforms (flat top sides) into the top of a square in progress allows more than one such square to be built at once, keeping options open for handling any tetromino.
The New Tetris was developed prior to the standardization of tetromino colors.
The diagrams below, like most other diagrams in Tetriswiki, use Tetris Worlds colors per the more recent Tetris Guideline.
If two of the same 2×4 constructions are put together, monosquares are formed. Alternatively, two different 2×4s can be put together (or one sandwiched between two I pieces) to make multisquares in addition to those below.