The idea of driving a nail into the ground may seem like a strange one. But it is a traditional practice in petanque to drive nails into the ground to hold strings and backboards (boards for wooden surrounds) in place.
One of the grand traditions of petanque are pictures and postcards of Fanny. In this one, I’d like to direct your attention to the backboards on the ground. Note that they are being held in place by big nails.
Here is a video from Spain. Starting at the 1-minute mark, it shows them stringing a piste using red wooden pegs. Perhaps that’s the way they traditionally do it in Spain, but I’d call that a trip hazard. Better to lay out a piste with nails and string.