Fore!

Our local woods skirts Bridge of Allan golf course and a lot of golf balls end up in the woods.

Well I collect them ( and so do many other people).  So I decided the other day when we had young visitors to do an art installation in the woods using the found golf balls. 

I placed them  in lines across fall trees. As expected most disappeared within hours but these did remain, maybe beause they were hidden.

Why "fore!"?  There is a golfing rule that if you think you might hit someone  you are required to yell:"Fore!" meaning "Look out!"