The simulation to the left illustrates one of the simpler ways that complexity can arise in the world. What you're looking at is a yellow-brown liquid film containing medium-brown nanoparticles. The dark-brown patches are dry spots where the liquid has evaporated. The nanoparticles are free to move where there is liquid to lubricate their movement.
The parameters of the simulation are:
Coverage = The proportion of the cells that start filled with nanoparticles.
εl = The energy of a liquid cell adjoining another liquid cell.
εnl = The energy of a nanoparticle cell adjoining a liquid cell.
εn< = The energy of a nanoparticle cell adjoining a nanoparticle cell.
μ = The energy of evaporating a liquid cell into a dry cell.
Pmove = The probability that a nanoparticle attempts a movement.
This simulation was described in Drying-mediated self-assembly of nanoparticles by Eran Rabani, David R. Reichman, Phillip L. Geissler & Louis E. Brus, in Nature 426, 271-274 (20 Nov 2003).
The simulation was built with the Processing programming environment. The Processing source code: mudcrack.pde
Other implemetations of the simulation were built with StarLogo and with NetLogo. The StarLogo source code: mudcrack.slogo. The NetLogo source code: mudcrack.nlogo.