jquery.box2d.js is a simple jquery plugin that transforms DOM elements into actual physical objects. well, physical in a flat 2d-browser-world.In Short about box2d :
we clone the selected DOM elements into absolute possitioned … well … clones.
we animate them via dynamically (javascript styly) set CSS3 transforms / translate / rotate combos
the values for this CSS/javascript mambo-jumbo are calculted via box2d-web