THE IDEA IS : " I WANT TO SEND A LETTER FROM A PLACE WHERE I'M NOT. "

Have you forgotten to send a letter from where you were on holiday ?
Would you like to make a surprise to a friend, wishing him (or her) a happy birthday from the other side of the world ?
Would you like to make your relatives believe you're abroad ?
Would you like to send a message to someone who mustn't know who you are ?

NO PROBLEM !

THEN :

AND FINALLY :