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.
Naive micro-optimization of your program (namely, things like FF is 1 char shorter than [F]) got that down to 40 chars:
[[[[[[[[[[[[[[[FF]]]]]]]RRF[RRR]]]]]]]]]
I then found a solution in 37 which uses a slightly different approach (namely, create a pattern that spans the full X and Y output space, then shift it by one step each iteration):
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.