A similar effect, when animated with a function like `color = (y == (x ^ t))` for varying values of t, is called “munching squares.” It was originally written

A similar effect, when animated with a function like `color = (y == (x ^ t))` for varying values of t, is called “munching squares.” It was originally written for the PDP-1 in the early sixties. I’ve seen it demonstrated on the Computer History Museum’s PDP-1. I always wondered how the characteristic “XOR texture” could be produced if the PDP-1’s display can only plot points and does not use a bitmapped framebuffer. Turns out it takes advantage of the long persistence of the screen’s phosphor, and the brightness of each point decreases over time. The CHM has a video of it running online, but it does not capture the effect of the phosphor persistence: https://www.computerhistory.org/collections/catalog/102664156 https://www.computerhistory.org/collections/catalog/10266415... Edit: here’s a video of it running in MAME that somewhat shows how phosphor persistence creates the XOR texture: https://youtu.be/AxJzUiaQ7xM?si=X9K47c4WyD6AisUp https://youtu.be/AxJzUiaQ7xM?si=X9K47c4WyD6AisUp