Brass Kaleidoscope
— fps · drag the eyepiece to turn the tube · scroll to fine-turn · ← → turn · space shake · double-tap or f for fullscreen (tap the black there to show the buttons) · s snapshot · on a phone, gravity follows the phone itself · Object → Camera turns it into a teleidoscope, pinch to zoom the lens
Built the way Brewster's original works: two front-surface mirrors meet at an angle, and whatever sits in the wedge between them is reflected around the apex. 60° gives six-fold symmetry, 22½° gives sixteen. The glass lives in a backlit cell at the far end and tumbles under gravity as you turn the tube, so no pattern ever comes back.
Made by Dusko Delic in Teddington, London, in September 2026. Free, no adverts, no account; the code is open under the MIT licence. Snapshots and the fullscreen view carry a small signature, as a painting does; untick signed below to leave them bare. More toys at duskod.github.io.