I have a strip of paper with parallel sides, a pencil and a straight edge. How can I construct a regular pentagram (star) with these? And for that matter, a pentagon? Well ... the pentagon is the proper way to go.

(In reply to re(3): A trick by SilverKnight)

Another curiosity of Brian's knot.....

Once flattened it is made up of sections where each section is made up of 2, 3 or 4 layers of paper. The area covered by those sections with 3 or 4 layers forms a pentagram. The 4-layer only section is a pentagon in the middle of the pentagram.

For the superstitious amongst you I'm sure that the posting of this problem on making pentagrams 39 (=3x13) days before Hallowe'en / All Hallows Eve / Samhain is pure coincidence so fret ye (k)not.
;-)

Posted by fwaff on 2003-09-23 03:52:27