I prefer: sphere, tetrahedron and cube-multi-dimensional movement patters.
I like that idea.
Myself, I prefer the ellipse instead of the circle, when it comes to aikido - and all budo. For example, I like to think of the relation between tori and uke as the two focal points of an ellipse - each person's center being one of them.
There are no circles in the universe - only ellipses.