Image caption, Use your hands to fold the paper in half, lining the edges and corners up neatly Here we chose to fold from left to right. Whichever way you fold your paper, use your fingers to ...

For amusement he began to fold the trimmed-off strips of paper in various ways ... by pinching together two of its triangles. The inner edge of the two opposite triangles may be opened with ...

The reason why fitted sheets are so dang hard to fold is that they have stretchy, rounded edges. It's obvious how to fold a square object but folding a rounded one? That's a little tougher.