Technical data for this type of fractal : click here.

For the fractal here :
fn1 = ident(), fn2 = acos(), fn3 = ident(), fn4 = ident()
real(p1) = 1, imag(p1) = 16, real(p2) = 2, imag(p2) = 0, real(p3) = 0.36, imag(p3) = 0.0648