Moiré Interference Weave Screensaver
A moiré pattern is a real optical interference effect that appears whenever two repeating line or dot grids overlap at a slight offset or angle. This screensaver overlays two real independently rotating line grids — the shifting wave-like pattern you see is produced entirely by their overlap, with no separate pattern drawn anywhere.
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How the Moiré Interference Weave screensaver works
Two real fine line grids are drawn on top of each other, each one rotating continuously at its own independent, slow real speed.
Wherever the two grids' lines nearly align, light passes through more freely; wherever they cross at a sharper angle, the overlap looks denser and darker.
That density variation is the real moiré effect — a genuine optical interference pattern that exists only in the overlap, not in either grid individually.
Because the two grids rotate at slightly different real speeds, their relative angle keeps changing, so the moiré pattern continuously reshapes and drifts rather than sitting still.
Moiré patterns in art, print and physics
The word moiré comes from a French adjective for watered silk, a rippled fabric made by pressing two wet layers together. The effect occurs whenever two regular patterns overlap with a small difference in spacing or angle. The eye reads the slow beating between the two periodicities as a new, much larger pattern, in the way two nearly equal musical notes produce a slow throb.
Moiré turns up well outside art. Full-colour printing overlays halftone dot screens, which inevitably produce some moiré, so prepress work involves choosing screen angles and frequencies that minimise it. Engineers use it deliberately: in strain measurement a deformed grid is compared with a reference grid, and the moiré pattern is much larger than the deflection that causes it, which makes small movements easy to read.
In physics, stacking atomic layers with a slight twist gives moiré patterns of the lattices themselves. In 2018 a team led by Pablo Jarillo-Herrero and Yuan Cao at MIT reported superconductivity in bilayer graphene twisted by about 1.1 degrees, a field now called twistronics. For two line patterns of equal pitch p rotated by a small angle α, the pale fringes sit about p/α apart, so smaller angles give broader bands.
A worked example
Watch a set of wide, sweeping dark bands slowly rotate and narrow as the two grids' relative angle changes — pause and compare either grid alone and you'll see it's just straight lines; the wave pattern only exists in their combination.
Settings & tips
- Grid A color and Grid B color recolour each rotating grid independently for a stronger interference effect.
- Rotation speeds differ slightly between the two grids by design, so the pattern never repeats exactly.
- The clearest bands appear when the two grids' angles are closest together.
Frequently asked questions
- Is a moiré pattern a real physical effect?
- Yes — it's a genuine, well-documented optical interference phenomenon that occurs any time two fine repeating patterns overlap, from window screens to printing to fabric.
- Is anything actually drawn to make the wavy bands?
- No — only two sets of straight lines are ever drawn; the wavy bands are a real emergent effect of their overlap, not a separate shape.
- Is a key needed?
- No — it's a pure local computation.
- Is it free?
- Yes — free, no download, in your browser.
- Why do small rotations make large patterns?
- For two line patterns of equal pitch, the fringe spacing is roughly the pitch divided by the angle in radians. A tiny twist makes the lines drift out of step only slowly, giving wide bands.
- What is twistronics?
- It is the study of how the twist angle between layers of two-dimensional materials changes their electrical properties. In 2018 an MIT-led team found bilayer graphene twisted by about 1.1 degrees superconducted at about 1.7 kelvin.