ongoing experiments with Nordic flag design. decorative stitching at edge shows the colors of the original two flags. Colors are my own guesses about the mixture. Another piece will show the official colors and exact mixtures thereof.

Also worth trying: In a nod to the rule of tincture, add fimbriations (instead of decorative stitching). Blue/purple boundaries get azure on the inside and argent on the outside; orange/purple boundaries get gules on the inside and or on the outside. (Maybe only single fimbriations, with the metals, construing orange and light blue as colors; but in origin they are half metal and half color, and the double-fimbriation proposal respects that.)