Thorn Fractal

This fractal is created by iterating the functions (x_n,y_n) and shading each pixel (x₀,y₀) depending on whether or how fast the series escapes to infinity. The parameter (c_x,c_y) is gives (slightly) different fractal images.

xn xn+1 = + cx cos(yn)

yn yn+1 = + cy sin(xn)