He hums slightly in acknowledgment, already crossing over to the pile of rubbish behind one of the restaurants. A broken crate is overturned to form a makeshift surface; then he sifts through some of the discarded clamshells until he finds three that are reasonably identical.

A little pebble is placed beneath one of the shells; all three are placed on the crate, which Byerly seats himself behind.

"Observe," he says, and lifts the shells to show the one with the pebble. Then, with the deft hand of a true master, he begins spinning and weaving the shells in between one another, forming a dizzying pattern. Finally, he comes to a stop:

"Which one?"