When wave pass through each other, they interfere, producing neat effects. Artist Gary Drostle harnesses the interference patterns as light passes through rippling water to create fish pond mosaics.

Wave Interference in a Fishpond Mosaic

The first pond is Trompe L'oeil (left), a mosaic fishpond in Croydon, Surrey, while the later upgraded Deep Pond mosaic fishpond (right) is in Chiswick, London. Both use changes in colour to evoke the interference patterns traced by light passing through ripples on the surface of shallow water.

The bright white circles and curves, and the correspondingly darker shadows, trace the constructive interference of the water waves. Where the crests align with crests or troughs with troughs, these higher amplitude waves create more extreme concave or convex surfaces. The water waves act as lenses that refract the light more severely into patterns of sharper contrast. Destructive interference, where crests and troughs cancel out, leave patches of stillness on the water, allowing light to pass through without focusing or divergence.

Images courtesy of Gary Drostle. For more optical illusions in design, check out this patio, or the visually-similar Super Guppy cargo plane.