Hold your four sheets of paper hamburger style.
On the FOLDED side, make a mark one inch from the edge. Repeat on the other side.
Make a small cut on each mark (on the FOLDED side!!!).
Separate into two stacks of two papers each.
With stack #1, make a small cut from the edge of the paper to your previously made cut. Repeat on both sides.
With stack #2, make a cut along the spine between the previously made cuts.
Insert stack #1 into the hole in stack #2 like so.