TETRIS GLOSSARY
Base
Also called T-spin base · TSD base
The supporting shape under a planned T placement. A complete spin setup also needs the correct surrounding corners, an accessible entry and usually an overhang.
View in the A–Z glossary →Related terms
Overhang →
Blocks extending above empty space. An overhang can enable a spin or tuck, but also blocks a straight drop. Always check how the required piece will actually enter.
T-slot →
A cavity intended for a T piece. A T fitting inside does not automatically earn a spin: the entry, final action and occupied corners must satisfy the game's detection rules.