Technical data for this type of fractal : click here (C06-010).

For the fractal here :
fn1() = ident(), fn2 = tan(), fn3 = tanh(), fn4 = tanh().
real(p1) = 0, imag(p1) = 16, real(p2) = -16, imag(p2) = -1, real(p3) = 1, imag(p3) = 2

Zoom on the top of the yellow circle :