New balls please... and lots of them

You didn't know there was going to be a quiz, did you? No, nor did I.

But when I was on Number 1 Court today, a little under an hour before the first match was due to start, I saw these three fellows. I watched them as they took a basket of balls and then began laying them out across the court. They studiously laid them out, first one half, then the other. And no sooner had they laid them out, than they started to collect them all up again.

I asked three security guards and two members of the public what they thought was going on. The replies I had included 2 x "Don't know", 1 x "Don't care", 1 x "It's performance art" and 1 x "It's to do with satellites overhead".

So...now it's your turn. Add a comment to this post and let us know what you think is going on. Don't be shy - there are no 'wrong' answers (well, ok, yes there are, but that's not the point). Have a think and post your ideas/guess as a comment.

I'll reveal the answer in a day or two. There is no prize - just my admiration. And money can't buy that (again, not strictly true).

And gypsum? You're not allowed to comment on this one, because I think you know :o)