Cucaracha
Here’s another Processing applet. It’s a variant of Bees, but it uses a Mexican Hat function for computing the force. Basically that means that they’ll try to stay a specific distance (in this case ~80 pixels) away from you. This also includes the motion blur from the Blend Cube sketch.
This one’s written in Java because I’m still having some trouble packing up applets from Scala.
Our favorite trick with this one is to let them settle down into a circle, and then give the mouse a tiny little twiddle. Enjoy.