Thank you for taking time to explain. The point about other ukemi fitting the wheel shape and a breakfall not fitting that shape was particularly helpful. I had not thought about it that way. But it makes sense. I would tend to think of it as more of an elipse since the shape seems to me to be more of a vertical oval than a circle.
It will be interesting to see what other people might like to share as to their concept of what a breakfall or high breakfall is as well. I would find it beneficial to see other perspectives.
I'm not much on math but if someone would care to explain how linear algebra and vectors relate to brealkfalls I bet that would be quite an interesting read.