The ball was another yard decoration (meant to be planted in patterns in flower beds). I placed it in the bowl to further weigh it down just in case a thunderstorm might blow through while we were out. It has survived a year of weather without moving, although we would secure it in the event a hurricane threatened. The bowl and ball together weighed 20-30 pounds. The bowl had a very low center of gravity, and nubbies underneath to prevent just this sort of accident. It was specifically designed with this application in mind: outdoor flower pot/decoration, meant to be placed on a fence, shelf, rail or pedestal.

I found the ball in the lawn, on the opposite side of the fragments of the bowl in the porch. I suspect the bowl and ball fell into the porch, the bowl shattered, and the ball rolled around off the porch and into the yard. I.e., the position of the ball is not a mystery, the fact that bowl fell off its perch is.

The only thing I could imagine would explain this is someone walked up, shoved the bowl into the porch, and walked away. I didn't hear anything inside the house, but it must have made an awful racket.

The weather was dead calm today.

This is the bowl, about a foot across.

The stone ball rested inside, kept from rolling around by the drain hole in the center of the pot.

http://www.google.com/url?source=imglanding&ct=img&q=http://allthingsplants.com/pics/2012-07-14/MamaIve12/83ef4e.jpg&sa=X&ei=Kko2UtK5NYSG9QT8ioGwBg&ved=0CAkQ8wc4kAI&usg=AFQjCNF9fbI5mcEVD08GiGqv9iUpshmDFg