Which statement is incorrect about the Tetris game?

Concept

Tetris clears a row using a purely positional rule: a horizontal row is removed only when every cell across its full width is filled by some part of a tetromino, leaving no gaps. This check depends only on whether the row is completely filled - it does not look at the color of the blocks in that row.

Application

Checking each statement in the question against this rule:

• The claim that Alexey Pajitnov created the game in 1984 is a documented historical fact about the game's origin, so it is accurate.

• The claim that the falling pieces are called tetrominoes matches the standard terminology used for the four-block Tetris pieces, so it is accurate.

• The claim that the grid is 10 columns wide and 20 rows tall matches the standard Tetris playing field, so it is accurate.

• The claim that lines clear by aligning blocks of the same color does not match the row-completion rule above, since color plays no role in whether a row clears.

Cross-check

Checking against the official rules confirms this: a completed row disappears simply because it has no empty cell left, regardless of whether it contains one color of blocks or several different colors mixed together. No Tetris ruleset ties line-clearing to color matching, so a statement built on that idea cannot be an accurate description of the game. Since the other three statements are accurate, the statement about clearing lines by matching colors is the one that is incorrect about Tetris.