Click the green flag. Simulates fractal branching, for example in crystal growth, through diffusion limited aggregation. Click Brownian for random jiggling. Particles randomly move until touching a stationary particle. Over time particles form a tree-like fractal shape. If you click Radial the particles start from a random position and move in towards the center. Notice the difference between the Brownian and Radial.
This is Diffusion Limited Aggregation, a simple model of a common growth process in nature. Particles randomly move (Brownian motion) and stick to other stationary particles (If you click Radial, then particles move straight inwards). At the start there's only one stationary particle, a "seed." So I started with a picture of a green dot in the center. I also had one Sprite, which is yellow. That yellow Sprite makes clones of itself and each moves around, When a clone touches any green, it stops. We make clones turn green so that moving clone knows it isn't moving when it touches green. Yet we can still color a bit by adding a small penmark in the center of each clone. We stamp clones and delete to get around the Scratch clone limit of 300.
