I've searched, and searched, and searched for any guidance on how The New Tetris handles collisions, and I'm coming up very empty. It clearly has some funny logic going on, and I'm having a hard time nailing down exactly how it decides if a rotation is valid or not. This is a separate, although related, system from its wall kicks. Reference building a square from L or J pieces in the most efficient manner: http://tetrisconcept.net/wiki/Square_Platforming 000 **0 * * When you have the first two pieces in place, as shown above, the fastest method to place the third is by hard dropping on top of the structure such that one block is over hanging: xxx 000x **0 * * Then rotate clockwise twice. This results, however, in the majority of the piece intersecting with the structure, but causing no collision. Anyone have any guidance??