Updated
ulam
A mouse-driven spiral of primes, evens and odds.
What it is
A full-screen animated spiral of 5,000 dots, each colored by whether its index is prime, even or odd. Moving the mouse reshapes it as you go: left and right for the angle between dots, up and down for the starting distance.
Despite the name, it is not the classic Ulam spiral, which lays integers out on a square grid. It is a live companion to spiral, with the same polar layout and colors, redrawn every frame.
How it works
- Pts.js provides the full-window canvas and the animation loop.
- Every frame, all 5,000 points are recomputed from the current mouse position.
- Primes are magenta, even numbers yellow and odd numbers cyan.
- The whole thing is a single HTML file.
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