Puzzle 1. Fold the side AB so that it lies along BC, and find E so
that BE equals AB. Then unfold the side AB. See Step 1 in the Solution to
Now fold the strip as shown in Step 2; point A lies on EC. This will give
you the point F.
Fold the strip back as shown in Step 3; its edge AC lies along AB. This
will give you the last point G. You already have the shape of a perfect
Finally, fold the rest of the strip as shown in Step 4, and a perfect
pentagon is ready!
Puzzle 2. Neatly tie the strip in a knot, and then gently press it
(while continuing very gently to tighten it). This allows to make the knot
flat. See Step 1 in the Solution to Puzzle 2. As you can see the knot
itself is a perfect pentagon already. So now fold the ends of the strip
along its sides as shown in Step 2, and you get a perfect pentagon again!