I made a space-filling curve:
[[[[[[[[[[[[[[[[FR]]FRR]]RRRRRRF]]FFFFFFFRR]]RRRRRRFFFFFFFFF]]FFFFFFFFFFFFFFFFFFFFFFFRR]]RRRRRRFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF]]FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFRR]]
It's not very interesting by itself (it just fills the whole screen with white) but you get cool-looking visualisations of its fractal-like structure by putting "C" at different points of the opening brackets.