What you need:
-blunt scissors or a blunt knife
I used 6x4 cm boxes with 1 cm in between each two. That way, you can fit eight letters on your two pieces of paper. Make sure you leave a few cm at the bottom.
You can align all the boxes, or for a fun effect, make them swing from left to right.
-each letter is IN MIRROR VIEW! because you will later turn the page around
-each letter entirely fills a box, that way they'll all be the same size
-each letter is pretty thick, otherwise it will be too fragile
Make letters like Y, I and P that stand on one "leg" a little wider at the bottom, so that they'll stand stable once cut out.