How did soldiers fold thier letters in world war one?

[anna]

I want to make my history assignment, which is to write a letter from a soldier from world war one, look cool by folding it in the way that soldiers at that time did (I'm also making it look old to add effect). I know in world war two they used the v-mail thing when the letter was folded into a v shape. Could anyone tell me what method was used in world war one? Thank you.