I don't remember much from high school, let alone history. But I do remember about spheres of influence. http://en.wikipedia.org/wiki/Sphere_of_influence#Post-Imperial_China . I always thought it was an odd term because although countries had "influence" they definitely didn't have spheres.
Anyway, one day when I was coaching lehigh about dumping, we kept having downfield cutters cut into the dump area. Finally, I came up with a concrete visual that I think helped people realize the handler area and the cutter area.
Picture the field with the thrower trapped on the sideline, now imagine him with a 10-15 yard sphere around him. This is the dumps area. The dump has a 10 yard sphere of influence around the thrower. Cutters, generally, 99% of the time, should NEVER invade this sphere.
This 10 yard sphere exists around the thrower at all areas on the field. Let the dump be able to get to the dump. Leave those 5-8 yards in front of the thrower open for the dump to get it upline in the power position. This is a great position to huck from, and everyone loves to score goals.
Maybe i will draw a picture sometime..... probably not.