My next "Mathematical Enchantments" essay will be about chip-firing, aka the sandpile model on directed graphs. Or rather, it will be about the Polya urn model, which it will treat both randomly (using random walk on a small acyclic directed multigraph) and quasirandomly (using chip-firing on that same graph). I would really like the article to have, as a side-bar, a little JavaScript applet that will let readers play with chip-firing, to get a concrete feel for it. Would any of you (or your students) be able to create something like that in the next two or three weeks? It doesn't need to be versatile (in fact, versatility will be a minus if a plethora of buttons leads to a cluttered screen); it needs to be eye-catching and fun. Jim Propp