Left: Three circles with radii 11, 13 and 15 and center 0 as well as 18 points distributed equally on the circumference of the middle circle and beginning with the complex number z = 12 – 5·i  (marked with green color). Right: Images by the polynomium P(z) = z³ – 15·z² + (57 + 48·i)·z + (33 – 56·i) of circles and points. The image of the circle with radius 13 passes through the origin, because P(12 – 5·i ) = 0.
Own work
AstroOgier