Playground · Guilloché
The security patterns on every passport.
Drawn by maths, not by hand.
I have been looking closely at government documents lately. Passports, driving licences, the fine interlocking lines, guilloché patterns. They make a document feel trustworthy, and they are hard to forge because they are drawn by maths, not by hand. Once I spotted them, I couldn’t stop noticing them, on bank notes, watch faces and certificates.
The why
Guilloché is spirograph maths, repetitive geometric patterns. I wanted to create my own, so I built this generator.
Shaping the pattern
Three modes, Rosette, Wave and Lathe. These are the most common ones I’ve used, there are many others. Use the sliders to redefine and shape the pattern. Change the colour and export as SVG.
- Rosette: Flower-shaped spirograph pattern.
- Wave: Lines running side by side in a strip.
- Lathe: Rings inside rings, like ripples or a watch dial.
Advanced — harmonics, phase, scale decay, resolution, seed
Randomise rolls a seed and builds every setting from it. Type one back in to get the same pattern again; move a slider afterwards and the seed stops describing what is on screen.