Geometry Question -- Paper Folding Trick

Given a piece of square paper, fold it twice, and then cutting across all thickness, create a square in the middle of the larger square.

How can this be accomplished? I simply cannot figure it out.

It works!

So, a square folded 1, and again, than cut the corner (// to diagonal) where you have no paper edge. ===> a smaller square with the sides _|_ on the main square diagonals.