Optic Illusion — Apps From Outer Space, LLC

Seventy-two optical illusions in seven categories, each built from its real geometry rather than reproduced as a picture — and each with a plain-language account of what your eyes and brain are actually doing. Then measure your own, in four minutes.

Every picture here is honest. Your eyes are not.

Screenshots

Optic Illusion on iPhone: the Penrose Triangle rendered as three grey beams meeting in an impossible tribar, with the viewpoint control set to Impossible view, with the teaser and explanation below.

Optic Illusion on iPhone: the Penrose Triangle with Turn the camera selected, the figure sprung open into three separate beams that plainly do not meet, with the teaser and explanation below.

Optic Illusion on iPhone: Rotating Snakes, nine static wheels of black, dark grey, white and light grey segments on a grey field that appear to drift although nothing is moving, with the teaser and explanation below.

Optic Illusion on iPhone: Adelson's Checker Shadow, squares A and B marked on a checkerboard crossed by a cylinder's shadow, above a control offering to join them with a bar of the grey they share, with the teaser and explanation below.

Optic Illusion on iPhone: Negative Afterimage, a colour-reversed flag in cyan, black and orange with black stars and a fixation cross, above a control that swaps it for a blank white field, with the teaser and explanation below.

Optic Illusion on iPhone: Scintillating Starburst, concentric wreaths of short white arcs on black whose aligned gaps produce bright rays that are not drawn, with the teaser and explanation below.

Optic Illusion on iPhone: Kanizsa Triangle, three black notched discs on a pale field producing a bright triangle whose edges are not drawn, with a control that turns the notches outward, with the teaser and explanation below.

Optic Illusion on iPhone: Your Sensitivity Curve, a Campbell-Robson chart whose stripes narrow to the right and gain contrast downward, the inverted-U boundary where they vanish drawn by the viewer's own vision, with the teaser and explanation below.

Optic Illusion on iPhone: the gallery list, exhibits shown under the Motion heading with their category labels, one row each.