TETRIS GLOSSARY
Parapet
A donation using a J-shaped cover, or its mirror, to make a TSS or TSD above an open column. The spin clears the cover while preserving lower rows for a possible follow-up Tetris.
View in the A–Z glossary →Related terms
Donation →
Temporarily cover an open column to build a spin above it, then clear the covering blocks to reopen access. Check the post-clear board: a bad donation leaves the original gap buried.
Kaidan →
A TSD donation built along a stair-shaped edge, with S or Z forming the spin shape. It can repair awkward height parity while reopening the space underneath after the clear.