English: A regular dodecagon is either convex or stellated.  Given such a convex polygon, we can draw twelve equal diagonals without lifting the pencil, provided that any diagonal subtends an arc that measures  5 × ^360° / ₁₂  =  5 × 30° = 150°,  on the circumcircle of the dodecagon.  These diagonals are the sides of a stellated dodecagon, which has the same vertices as the initial convex dodecagon.  Each of these twelve segments contains a side of a concentric dodecagon, which is a reduction of the initial convex dodecagon to scale  tan 15° = 2 - √3.  We can consider this new convex dodecagon as a given dodecagon, in order to repeat the process:  we construct two other dodecagons, one stellated and the other convex, and two others again, more and more small, indefinitely.  We call this an infinite iteration of the geometric construction.