Technical data for this type of fractal : click here.

For the factal here :
fn1 = ident(), fn2 = cos(), fn3 = cotan(), fn4 = ident()
real(p1) = 2, imag(p1) = 2, real(p2) = 1, imag(p2) = 1, real(p3) = 0, imag(p3) = 1