The Doctor's card was more picturesque. It had a few Hanzi characters 
scrawled across it and also bore Dr. X's chop. Now that paper was smart, 
chops were dynamic. The stamp infused the paper with a program that caused it 
to run a little graphics program forever. Dr. X's chop depicted a 
poxy-looking gaffer with a conical hat slung on his back, squatting on a rock 
in a river with a bamboo pole, hauling a fish out of the water—no wait, 
it wasn't a fish, it was a dragon squirming on the end of the line, and just as 
you realized it, the gaffer turned and smiled at you insolently. This kitschy 
tableau then freeze-framed and morphed cleverly into the characters 
representing Dr. X's name. Then it looped back to the beginning. On the back 
of the card were a few mediaglyphs indicating that it was, in fact, a chit: 
that is to say, a totipotent program for a matter compiler, combined with 
sufficient ucus to run it. The mediaglyphs indicated that it would run only on 
a matter compiler of eight cubic meters or larger, which was enormous, and 
which made it obvious he was not to use it until he reached America.