Start by naming any country that France borders. Then name any country that borders any of those countries. Then keep going until there are no more countries left to name.
Why would I want to do that? I'm not from the Anglophone world. Taking your comment into consideration, I have opted for spaces, which seems to be the international standard since 2003 :)
Okay, but this is the English version of JetPunk; in my English quizzes I always use separating commas, but in my German quizzes I use separating full stops.
Let's hope no one reads the comments before taking the quiz...