What optical illusion does this demonstrate?

This demonstrates chromostereopsis — the visual system's tendency to perceive warm-coloured objects (like the pearl marbles) and cool-coloured objects (like the indigo marbles) as existing at slightly different depths. Cool colours appear to recede while warm colours advance, creating a subtle 3D pop on a flat screen. The radial gradient shading on each marble also triggers shape-from-shading, making the flat circles read as three-dimensional spheres.

Can I export the animation as a video?

Yes. Click 'Export MP4' to render a high-quality 60fps MP4 video of the marble animation, complete with marble sound effects baked into the audio track. Requires a modern Chromium-based browser with WebCodecs support.

What shapes are available?

The marbles can be arranged in seven patterns: Circle, Diamond, Cross, Band, Ring, Corners, and Full grid. Each shape produces a different composition of the chromostereopsis depth effect.

Chessboard Illusion – 3D Depth & Chromostereopsis

Columns

Rows

Marble size

80%

Shape

9 × 9 checkerboard