More cool rolling shutter effects

Last week, Mark posted a shot of a boy blinking in a photo but with his eyes open in a reflection.

In the comments, several people explained that this was a rolling shutter effect. You can get something similar panning many DLSR cameras too quickly back and forth, causing a "jello" effect on solid objects. Commenter knodi shared a still of his propeller showing the same effect. You can get the same trippy effect in video based on the frame rate, as seen in Steve Talkowski's video above.