Sin Sinh Ladders

Newton's method applied to f(z) = sin(z) sinh(z) - 1, centred on the origin at width 10. The roots fall into two interleaved ladders, one along the real axis and one along the imaginary axis, and evenness plus conjugate symmetry gives the frame a full fourfold reflection. Colour is keyed to which ladder the pixel converges to, rose-gold for the real ladder and steel for the imaginary one, with tone alternating by rung. Convergence is tested on the step |f / f'| rather than on |f|.