Technical data for this type of fractal : click here (C01-01).

Here :
fn1() = sqr(), fn2() = ident(), fn3 = ident(), fn4 = acosh()
real(p1) = 0.5, imag(p1) = 13, real(p2) = -3, imag(p2) = 0, real(p3) = 0, imag(p3) = 0