Animated Brushes 4
A little experiment with 'Animated Brushes'. There are 20 'wanderer' brushes that either (a) wander about aimlessly or (b) wander towards the mouse if you click and hold the mouse somewhere in the canvas. These 'wanderer' brushes are not drawn. There are 300 other brushes that pick a random wanderer and head towards its, occasionally changing wander mid journey. If you leave the animation running for a short while, eventually all the brushes group near the middle of the canvas in an hypnotic swirl. Source is here.