Quartz Quartet

Newton's method applied to f(z) = z^4 + i z^2 + (1 - i). Every root is simple, so convergence is quadratic and the smooth count takes the log-of-log form. The function is even, so the field carries an exact 180 degree rotation and the four basins fall into two congruent pairs with no mirror. The window is centred on a free critical point of the Newton map, a zero of f'' = 12 z^2 + 2i, at 0.28868 - 0.28868i and width 0.88, where the lace is richest.