I used to work at a golf course and when I wasn't golfing or mowing fairways I was hunting for golf balls. My hobby of collecting golf club logo balls expanded to logo balls in general. At one time I had over 7000 golf balls in my collection. Part of the colored golf balls I found went into building a pyramid shown above; 650 golf balls.
Leslie - I kept all the colored golf balls I found in a box and decided to do "something" with them rather than hide them away under a bench. I had seen a picture of a pyramid before and speculated I could manage a fairly good size pyramid with the golf balls I had found.