I'm working on one of these too - have lots more piecing to go, but have also been thinking of the finishing - I'll be bordering mine in an unconventional way - not cutting "half" triangles for the sides, but a rectangle with the proper angle added to the final triangle at each end of each row, then square up the outside edge of rectangle so my pyrmids will all be full size, and "float" within the border. I haven't see this done anywhere yet - maybe it is, but that's what's on my mind. I can't wait to see how you finish yours!