This glossary of gestures will come in very handy at your next TED talk. Example:
The Shelf Sweep.
Begin with both hands at right hand shoulder. Sweep across the top shelf of imaginary bookcase. When level with left shoulder, make sharp rotation of wrists and sweep across lower shelf.
Use when explaining hierarchies.
This post is only partially tongue-in-cheek. Body language is an important element of communication, and using the right gestures is certainly as significant as idiom choice when signaling your membership in a particular social group.