How to achieve this kind of effect? (new user)

Hello everyone, my first post on this forum.

I have just started using GH and used it only for some experiments with attractors so far (simple ones - planar circles with curves or points as attractors). I would like to achieve kind of organic web effect closed between surfaces or inside solids. I found some pictures on this website and on google as reference photos:

http://www.grasshopper3d.com/photo/marching-cubes-wrapping-breps-as... (thats exactly the kind of form im seeking)

http://archimorph.com/2011/10/13/morphogenetic-structuralism-2-00/ (this shrink experiment looks awesome, the red thing inside is exactly what i mean)

http://www.grasshopper3d.com/photo/zellstruktur-w-rfel?context=user (this ones voronoi i think, but is 3d and closed in a cube, thats more or less what i would like to get, the walls would be solid though)

Could you please post me some tutorials / simmilar definitions to analyze. I guess it will be a hard thing for a new user to understand and make, but im sure that with your help its possible :). Thanks!