Step 2: Fold the upper left hand corner down until it just touches the crease (see figure below).
Show that the triangle folded over is a 30-60-90 degree triangle.
Step 4: Fold what is now the upper left-hand corner down to touch the bottom of the bill
(see figure below). Remarkably, it will end up at or very near the lower right-hand corner.
Step 6: If all the creases have been sharp, you can now gently open up the dollar bill, and when
you put it down it will form a tetrahedron (with a picture of a pyramid on one side!). See
figure below.