Moiré pattern generator

What a moiré pattern is

A moiré is a large pattern that appears when two fine patterns overlap or when a fine pattern is seen through a grid. The name comes from moiré silk, a fabric pressed so that its threads produce a rippling, watery sheen.

You have seen it on a striped shirt on television, on a screen photographed with a phone, or in a scanned magazine picture. Printers fight it by turning each ink’s halftone screen to a different angle. Designers and artists use it on purpose, because it creates movement from almost nothing.

Why a coarse grid makes moiré

When a function changes faster than the grid that samples it, the samples alias: they no longer follow the function and draw large shapes that are not in it at all. Sampling theory says you need at least two samples per cycle to capture a pattern; below that, a new, slower pattern appears instead.

This tool makes that happen on purpose. It evaluates a formula on a grid of large cells and cuts the result to two colors with a threshold. Fine rings become wide bands, smooth curves become staircases, and moving the function under the fixed grid makes the moiré slide and change.

What each setting changes

The presets are Plotter moiré, Horizon bands, Fine rings, XOR blueprint and Interference.

• Formula: product x·y, hyperbola 1/y, rings x²+y², bitwise XOR or interference.
• Frequency A and B: how fast the function varies. Higher values give stronger aliasing.
• Threshold: where the cut between the two colors falls.
• Offset X and Offset Y: move the function under the grid.
• Cell width, Cell height and Origin at center: the sampling grid, and where the function starts.
• Speed: animates the function.
• Ink, Paper and Invert: the two colors.

What designers use it for

• Black-and-white posters and covers with a technical, plotter-like feel.
• Animated backgrounds for music, tech and event visuals.
• Patterns for print where the moiré itself is the subject, not a defect.
• Glitchy textures and transitions in motion design.

Tips

Moiré lives at the edge between too fine and too coarse: change Frequency A slowly and watch the pattern flip. Wide, flat cells (large width, small height) give horizontal staircases; square cells give the classic checkered moiré. Keep the speed low for backgrounds. Remember that compression and screens can add their own moiré to fine patterns, so preview your export at its final size.

Build another moiré tool

Two overlapping line screens, rotating circles, moiré type: describe the one you have in mind and Blueprint builds it with its own controls. The op art generator on this site was made the same way.