Boules de fort rink.

Came across this in Candes Saint Martin, on the south side of the Loire at the confluence of the Vienne.
Supposedly invented by sailors who were used to playing onboard when at sea.   The boules are very heavy, presumably to mimic the cannonballs used originally. needing little effort to set them off snaking from port to starboard in a multiple "S" track to the down hill end, making sure to avoid the central barrel.
Extra = The Loire.