Motivation

At the Exploratorium in San Francisco, there’s an exhibit (refer to the figure below) where a horse gallops across etched glass panels, animated by strobing LEDs.

To make a digital GIF of a horse galloping at 60 fps for one second, you need 60 frames. Each frame costs essentially nothing—it’s just bytes. But in a physical zoetrope (what this is), each frame is a hand-etched mirror or a sculpted object. The cost per frame is presumably enormous.

A physical zoetrope exhibit at the Exploratorium

I captured this at the Exploratorium along the Pier in San Francisco. Ghost Horse, by Michael Brown 2024. Inspired by the Muybridge racehorse.

Formal challenge

Are there configurations of geometry, lighting, or optics that let you achieve kk fps perceived motion with fewer than kk physical frames? What’s the theoretical minimum? What does it depend on—the symmetry of the motion, the number of light sources, the observer’s perceptual system, some combination?