There are many shapes in nature but the sharp ones grab at our attention and for good reason. A thorn in the brush or under our bare feet can mean an infection or a loud noise that can mean our end. It is also a great power generator if you want to cut or break things as you direct a lot of power on a very small surface. To use this fear to our benefit and to learn to use the feet better take a board which has hard corners like a construction wood piece and hold it in one hand. Move it using your bare feet and legs and feel how the pressure and tension change when you handle the edges. Have a friend push and direct you using all heights and angles and move with your entire body to protect yourself from harm and decide where you want to be instead of being led. If you have more than one partner and a few pieces of wood it is a good practice and also a good level work for them. Continue to strike with the boards (and whatever else is there) and see how you develop your own movement and remember to breathe and keep the eyes relaxed. It is hard to see the bigger picture but it raises your chances at survival.