TetriNet Rotation System

The PC based multiplayer game Tetrinet uses its own rotation system. Tetriminos spawn with a random initial rotaiotn, below the ceiling, in the center (rounded to the right if needed).

Basic rotation
The tetriminos rotate as described in the picture. I, S and Z alternate between two different states. The logic behind the uncommon and somewhat irregular behavior of J, L and T could be that all rotations of all tetriminos are placed top left in the bounding box (with the exception of I).

Wall kicks
Tetriminos can kick out from the walls of the playfield but not from walls of blocks. There are no floor kicks.