notes.husk.org/likes images.

Elastic athletes:

OK, so now imagine taking a flatbed scanner sensor and setting it up vertically, looking across a racetrack at the finish line. Start a “scan”, and it’ll authoritatively tell you when every body-part of every runner makes it to the finish, by simply showing that part of that person before any part of anyone else. The speed of the scan should be set to roughly match the speed of the runners, so they look generally the right shape, but any part of any runner that stays stationary relative to the scan rate - a foot on the ground, for instance - will seem long. Any part that’s moving forward relative to the scan rate - a hand or foot coming forward, for instance - will seem short. Even if you mess up the scan rate so everyone looks wide or narrow, whatever part of whatever runner shows up first in the scan is the first to cross the finish line.