Wouldn't this be a nice gift to make?  But also learn a new technique.  You already know how to do a 90 degree corner, but do you know how to do a 120 degree miter? Carolyn Reese will teach you how to use a new tool, it is the binding miter tool.  With this tool you can do a 90, or 120 or 135 degree miter.  So you can use it with squares, rectangles, hexagons, and octagons.

Class cost $20 Pattern $9 and miter tool $6