Back-to-Back T-Spin Triple

Back-to-Back T-spin Triple is a difficult maneuver in some SRS based games, which in (for example) Tetris DS sends a total of thirteen garbage rows to the opponent. It requires the player to make two T-spin Triples Back-to-Back.

Setups notched on side
LT/JT, the simplest set up. Its flaw is its heavy dependence on T tetrominoes, which could otherwise be held to complete the T-spin.

Setups involving S and I:

The core of JTTL can be replaced with two S or Z tetrominoes:

OZJ is arguably the safest and most efficient BtB T-Spin Triple setup. The setup is special in that it takes the least amount of tetrominoes to set up the notch. The player is also given 7 columns of space to stack freely. Perhaps the most unique aspect of this setup lies in the fact that one of the T-Spin Triples can be turned into a T-Spin Double by placing an I into the empty column, a scapegoat for ill-fated garbage. This must be done before the final "lid" piece have been placed at the top of the setup.

Setups notched in center
Setups containing I:

Switching sides
A player may switch sides to clear Back to Back T-spin Triples indefinitely.

Any T-spin line clear is good enough to keep the "Back to Back" alive, which allows for lopsided designs.

These two have interchangeable parts.