As I am working on my sample of the technique, I picked up another tip:
always cut a straight edge on the pieces you are putting together before joining the next section ... and, because of the angles you are cutting, there will be uneven edges ... so handle yourself accordingly.
Also ... for those on the periphery, watching and wondering, I came up with an idea ... forget all the angles ... you can do this same thing with straight lines .... as in, a nine patch? or just about any block, I am thinking ... back to the sewing machine.