I've been wanting to do this too. With the high price of outdoor decorative flags, it seems a perfect way to be creative. The only way I have seen was in a craft show with a company that made the banner flags that wave like a feather. They used kite material and a hot knife to cut it. That sealed the edges. Then they used a black zig zag stitch to bind the edges together. At least that was all I could get out of the guy who made them. I am interested to see of other ideas too. Your idea of embroidery would be great.