Picture credits
The illusion drawings are our own. The photos are public domain or CC0 on Wikimedia Commons, cropped and resized with no other changes.
Photos
Moonrise from Yavapai Point - December 7, 2022 -1712 (52889111041).jpg
by Grand Canyon National Park Service, Public domain
Our own drawings
Drawing of a room seen through a peephole, with a giant person on the left and a tiny one on the right
Our own drawing
Two coins drawn as discs, one big and one small
Our own drawing
Two equal purple discs, one inside a big ring and one inside a ring only a little bigger
Our own drawing
Two equal orange circles, one ringed by big circles and one ringed by small circles
Our own drawing
Two identical curved shapes stacked one above the other; the lower one looks bigger
Our own drawing
A drawing of two equal moons, one low over hills and one high in an empty sky
Our own drawing
Two horizontal lines of equal length, one with arrow fins pointing in and one with fins pointing out
Our own drawing
Two equal orange bars between converging railway lines; the top one looks longer
Our own drawing
Upright bars of equal height following a wave; they look like they change height
Our own drawing
An upside-down T whose upright and crossbar are the same length
Our own drawing
The classic illusions are old geometric recipes, and we drew every one from scratch. We don’t reproduce Roger Shepard’s drawings or the pictures on Michael Bach’s site; we link to them instead. Using these photos does not mean NASA, the National Park Service or anyone else endorses this site. Useless the eraser is the network’s own mascot. Fonts: Bricolage Grotesque, Newsreader and Kalam (SIL Open Font Licence), served from this site.