Tracery windows in an equilateral arch

This blog sees my first attempt to place a tracery window design within an arch. This picture was created using Cabri and edited on Paint...both free software. Because you cannot set a compass to a certain fixed width on Cabri (or if you can, please let me know how), this construction lacked the accuracy one could achieve using pencil and a pair of compasses. However it was fun to overcome the different challenges and am quite pleased with the final picture. Challenge yourself to do the same, or more simply, download the non-coloured picture and fill in the colours and embellish the design yourself. Do share anything you produce