Tetris modes decide when suspended blocks fall

Whether blocks fall into gaps depends on the game mode's rules for the stack after a clear. Standard Tetris shifts surviving rows downward by the number of cleared rows beneath them; variants can settle blocks farther or trigger a collapse only after a special move.

The standard rule does not simulate loose objects seeking support. The formal rules in Demaine and colleagues' Tetris study describe clearing a full row and moving the squares above it down one row. That explains an otherwise strange result: a square above several empty spaces moves only one row after a single clear beneath it, while a clear above that square does not move it at all.

This makes an unsupported-looking square a valid resting state. Removing the square below it does not automatically start another fall, because clearing rows and dropping the active piece are different operations. As a worked example of the standard rule, clearing two rows beneath a square moves it down two rows even if another five empty rows remain below its new position.

Some variants deliberately add another settling step. The original Tetris Worlds instruction manual describes Cascade Tetris as letting blocks fall after a clear and potentially complete more lines, while Sticky Tetris adds blocks of the same colour sticking together. The relevant distinction is therefore what the mode allows to move together and whether its settling can create a chain reaction; a visual overhang alone cannot identify the rule.

Other collapses have a specific trigger rather than occurring after every ordinary clear. The official Tetris Effect: Connected community guide says purple Magic Minos appear during Zone in Connected and Connected VS, and placing one cascades the blocks below it. That can make the same session alternate between a stable stack with holes and a sudden collapse, without requiring an inconsistency in the game.

Check the exact game, mode, and triggering piece before expecting a gap to close or planning a move around a cascade.