Bound 2D Collisions

Hi everyone.

I've been trying to use 2D collision to pack polygons inside a given geometry.

My aim is to Leave as little space as can be between them.
The polygons themselves are divided into 3 types - by area,
and hopefully also by proportions.

I've edited the collide2d script from the example files (kangaroo2),
and it starts very nicely.
But when the things get a little bit tight the curves penetrate each other
and it becomes a mess.

Is there a way to avoid this intersecting curves issue?

Thanks!

Video of the action and images below:

http://www.grasshopper3d.com/video/grasshopper-kamgaroo-collisions