Note: Sometimes the particles start in the four corners....I don't really know what's causing this, but usually if you just refresh it'll work the way it's supposed to.
I've been doing a lot of work playing with flash dynamic kinematics recently (read: I want to feel important by using big words) And a couple of people have wanted to see what I've been up to, so here's on of the prettier things I've done.
*WARNING, PROGRAMMING / PHYSICS CONTENT*
Pretty much I'm dealing with multi particle interactions in a bunch of different ways, this particular model assigns each particle a random mass (the physics definition: resistance to change in current velocity) and related size (the larger the mass, the greater the radius of the particle). Each particle begins with a random x,y velocity, but if they come within 150 pixels of one another, they will create a spring between the two (affecting at a rate of like 0.005, if anyone's interested....just lots of trial and error).
of note: there is a bug in this code that occasionally gives the particles disproportionately high velocities, so if you leave it on, the particles will just keep moving faster and faster. I have a version that has fixed this, but I kind of like how the current version works, so I'm leaving it up.