Make this - snail mail concertina pockets

This is a really simple way to create a little concertina of pockets in which to place gifts for pen pals. To make them, you just attach the top of one envelope to the base of another, to create a kind of concertina filled with snail-mail surprises. I first saw it on Pinterest and I THINK the link originally came from Martha Stewart, but I couldn’t find the source when I went looking. Cute, huh?