WWI Trench Warfare Names

Two armies are at war, each using the other's name as a target.

1915. The Germans are on one side, the French on the other. The Germans think: "All French are called 'Jean-Luc'. When we shout 'Jean-Luc' and they look up the trench we will shoot them." So the next few weeks it goes: "Jean-Luc?" "Oui?" Bang! After 5 weeks, the French think: "Les Germans are all called 'Ans'. If nous call 'Ans' les Germans will look up the trench et nous will shoot them." The next few weeks look like this: "Ans?" "Jean-Luc, is it you?" "Oui!" Bang!