acute or obtuse
greater resistance and flexibility an acute angle or an obtuse
Actually, I don't really care about those. My approach in training is to get what I want. Say training on a straight punch, I would first make it clear what do i want to do. Punch with a distance, punch after touch with no distance, punch to break the bone, punch to hurt the organ or punch through the body? After that, just do it and keep on putting in those ingredients that can help serving my goal. Those ingredients may come from the teachers, own experience and knowledge, or anywhere. With the practice, the angle, structure, stepping, flexibility, co-ordination, power, etc will kick in. The hardest part is how active I have to engage myself into. I would prefer the approach on doing it and let the body tells and follows what I want to do. It is the LHBF song and Five Word Song that bring me into this approach.
how do you topple a ball
Its a ball. No matter how do you topple it, the ball is still there as a ball. Nothing changes.