This page is created automatically. Click here to view this shader on Shadertoy.

Both rectangles are moving at exactly the same speed.

Based on the flash implementation by Jim Cash: https://scratch.mit.edu/projects/188838060/

Research paper:

https://quote.ucsd.edu/anstislab/files/2012/11/2001-Footsteps-and-inchworms.pdf

Source code

You can find (the full source of) Contrast speed illusion on Shadertoy.