A regular decagon, hexagon, and pentagon, each circumscribed by congruent circles form a right triangle that is half a #GoldenTriangle (half a #GoldenRectangle). Exquisite! Sketch with circles can be found by Clifford Pickover at https://twitter.com/pickover/status/1644439985532051456. John Cook noted, "When I first saw the illustration in Panoply of Pentagons (below) I thought that the top of the pentagon was parallel to the top of the hexagon. When I wrote the Python code first assuming this orientation of the pentagon, things didn’t line up. Writing the code made me pay closer attention, as is often the case." at https://www.johndcook.com/blog/2023/04/14/euclid-xiii-10/ #Python code reveals! #geometry #Euclid