I drew a 45 degree diamond in a drawing program, and more or less, if you used a strip of fabric 11 inches wide, and cut a diamond of that shape from it, it would be about 28.5 inches from tip to tip... amazing... that would fit the top of a queen size mattress just barely. The diamond in the picture below is that 11 inch strip... and I drew a wide darker color pair of strips inside the tip, then a slightly more narrow pair of strips for the white. Viola! The inside lines were drawn *freehand* so dont use this for a template LOL you need to make your own and get a handle on the pieces and sizing... Good luck.
[ATTACH=CONFIG]366508[/ATTACH]