Remember in junior high when you used to write notes and then fold them in a super complicated fashion in order to maximize the fun factor (while making sure they were also top secret)? Pigeon Post is like a more sophisticated version of that. Write a letter on one of the six patterned letter sheets in each box, fold it up, seal the fold with a well-positioned stamp, and pop it in the mail. The genius design dispenses with an envelope and will make the recipient feel the delight of passing notes in junior high all over again.