I thought surely a rectangular blanket would act the same as a square blanket. However, after sewing the corners and cutting them appropriately....you can see the corners were not lying flat. Even after trying to make the sides equal, those corners were not lying down at all.
I broke down and ripped out the corners and now, it lies flat, but I have these fantastic corners that have nothing on them.
Going to have to percolate on this issue for this week and see what I can come up with.