< Quadrangularis> "Given a certain prime set, with general element pi,j; under the inversion operation, pi,j→I(pi, 12 - j); that is, each element of the prime set is mapped into an element with identical order number but with set number the complement (mod.12) [sic] of the original set number." yep that's how music works
< ponicalica>  what's a prime set
< Runaround> @w prime set >! Wikipedia has the answer.
<@Omnipresence> : Wikipedia: Optimus Prime: Optimus Prime is a character from the Transformers franchise. Prime is the leader of the Autobots, a faction of transforming rob... — http://en.wikipedia.org/wiki/Optimus_Prime