Article 6 specifies that
Where a prefabricated (matérialisé) circle is used, it must be rigid (rigide)...
What kind of work is the word “rigid” doing in this sentence? When it comes to a plastic circle, what is the opposite of rigid? One of those folding plastic circles?
Plastic circles were introduced around 2004. If you go to YouTube and watch the 2004 final of the Petanque Masters, you will see something interesting.
At about 13:15 Claudy Weibel carries a plastic circle off of the terrain, while one of his team-mates brings another plastic circle onto the opposite end of the terrain. As Claudy carries it, the circle dangles from his hand like a piece of cooked spaghetti or a bicycle inner tube.
In the next few seconds, you can see his team-mate at the far end of the terrain placing the other circle. He doesn’t just throw it down and step into it, the way we do today. He lays it on the ground, then fiddles with it, and then fiddles with it some more, until he can get it to lay flat in a proper circular shape.
This must have been an early prototype of a plastic circle. This is what the opposite of rigid looks like.
You can see it again at about 22:33, and get a nice clear view at about 34:52. It really is limp and floppy.