Go back to Red B's post #50. The two papers he sites finally mathematically show a sprial to exist. BUT

BIG BUT

it is only 3 degrees off the centerline of the plane, hardly noticeable at all

Then there's John's bearskin test, great idea by the way. I'm always designing my test apparatus to the point nothing gets built or tested.

I haven't the faintest explantion for that one.