trees, rivers, lightning
a lot of things in nature follow this pattern.

from just looking at it with an uneducated eye, it looks like it is a function in which seperates with 2^n pathways starting at 2^0 = 1 (nice) then just continueing to branch with variability/randomness/chaos

are there well defined formulas for this and interesting books to read on this?

this is a cool read (first thing I found on google):
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3922496/

but just something more general and mathematical explanations