This question really only applies to Heboris using the SRS-X rotation system, because no other system (not even Nullpomino and Lockjaw using 180 degree rotation) seems to do this. http://harddrop.com/wiki/List_of_twists In sections 6 and 7 of the article above, it lists a number of twists that can only be done with 180 degree rotation in SRS. I tested a bunch of these, and all of them have worked in Heboris with SRS-X, but nowhere else. My question is, what kick tables does SRS-X use to determine where to place the block when basic rotation fails? I looked at the tables on the tetrisconcept wiki and the only rudimentary solution I could think of was that SRS-X attempts to do something like rotate right twice (without ever checking or rendering the intermediate state) using every possible combination of the 5 tests for each rotation, followed by doing it all over again for rotating left twice. While this theoretically works, it requires doing 50 tests for every double rotation, which is very inefficient. Does anyone know the actual algorithm used by SRS-X?