Unorthodox Line Clears

In games with recursive gravity that reward cascading line clears such as Tetris Worlds and Quadra, certain line clears discouraged in naive gravity (like in most games) allow you to score a perfect clear.

Reflection
A three-cascade example:

O Replacement
Due to the 2x2 nature of the O tetromino, the mirrored line clear formation is the same for both the S and Z tetrominoes.

J/L Replacement
The T tetromino can be used in the following situations where only the L or J could be used initially.