fractals.jelia.nyc
Zoom into a coastline, a fern, a lightning bolt or the Mandelbrot set and the detail never runs out. Each is built by repeating one small rule over and over, and the repetition is the whole secret. This site is a visual, hands-on guide to how that works, from the first "monsters" mathematicians drew in the 1800s to the glowing images computers paint today.
No maths background needed. It starts with what makes a shape a fractal, builds the famous ones with rules you can edit, dives into the Mandelbrot set with a live explorer, and ends with how fractal images get their colours and how a computer draws them in real time.