Currently I'm working on my PhD thesis. It isn't finished yet, but I decided the following images were worth a sneak peak:
Besides looking nice, the pictures actually convey some information. They're so-called Hasse diagrams of the root systems of a few affine Lie algebras. From left to right we have the following affine algebras: (a) A1+, (b) C2+, (c) D4+, (d) A8+, (e) D7+, and (f) E7+. But luckily you don't need to fully understand the mathematical background, which is admittedly quite complicated, to enjoy their beauty.