[…] play itself may be more usefully treated not as a form of activity but as a mode of experience […].
The game mechanic is the part of a game that separates it from a book, a movie, a photograph or even a conversation.
Play lies outside the antithesis of wisdom and folly, and equally outside those of truth and falsehood, good and evil. Although it is a non-material activity it has no moral function. The valuations of vice and virtue do not apply here.
Instead of the old saw “All is vanity”, the more positive conclusion forces itself upon us that “all is play”.
Game design, for me, is a constant “dance” between theme and mechanics.