Infinifactory - Geometrically-implausible rotation welding - Video
PUBLISHED: Feb 03, 2015
DESCRIPTION: When moving linearly, welding between two blocks requires a 1-cycle pause, but rotations seem to be more liberal with the collision detection. So if you're optimizing for cycles, you may want to tear a few pages out of your Geometry textbook.
Update: This trick doesn't work anymore, as of 2015-02-04.