While learning secondary physics in high school I often used the idea of the entire universe being a computer program to help me better understand how some things (Strong atomic forces, for example) would work by visualizing how I would program them should I need to recreate the same effect in a computer program. Now that I have a lot of spare time, I was playing around with the idea of recreating some very basic, but perfectly realistic physics simulations via a computer program. This got me to thinking, what would I actually Need to program? What I am really asking here is, how complex, in it's most basic form, is the universe? Aside from the 4 forces of the universe, what else is there coded into universal behavior? Basically, is the diffraction of light a side-effect of the existing forces acting in unexpected ways, or is that a basic property of nature? Do atoms form out of electrons, protons and neutrons just due to the core forces, or is there something else at work? Naturally I'd assume there would be plenty of quantum-level oddities to deal with too. Any insight into this would be appreciated, and any opinions.