See https://doc.sagemath.org/html/en/reference/dynamics/sage/dynamics/complex_dynamics/mandel_julia.html
julia_plot()
julia_plot(mandelbrot=False)
R.<z> = CC[] f = z^3 - z + 1 julia_plot(f)
julia_plot(period=[2,3])
R.<z> = CC[] f = z^2 + 1/2 julia_plot(f,interact=True)