As a child, many of us learned to fold a sheet of paper into a pinwheel or perhaps a box, an envelope, a hat, a boat, or an airplane. (Remember writing a note on a piece of paper, folding it into an airplane, and sending it flying across the school classroom?) These were all simple items to make. By mastering the techniques we used for these projects, we are then in a position to learn new folds and methods and move on to more complicated designs.