What are balls?
Balls are a spherical shape that has the diameter of PiR2. These
spherical object are made in many sizes both by man and by nature.
When man made, it is usually a child's plaything and is made of
rubber, latex, or other material.
Many types of balls for sports exist. Some of the more common
ones are soccer balls, basket balls, footballs, rugby balls, golf
balls, and tennis balls. Note that all these objects are different
sizes designed for the sport in which it is used.