This signature is called Efficiency mostly because it seems to be efficient for a right-hander. It enables the player to grab any piece without bumping into any others on the stash. Smalls are front-right, mediums in the middle, and larges on the back-left. Thus, you reach larger pieces as your arm swings back.
There could also be a mirror image of this signature for Southpaws, "Left-ficiency".
The Icehouse Signatorium