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THE GREAT STELLATED DODECAHEDRON

You are allowed to do two extra credit projects per school year.  You can pick the two terms you wish to do them, one per term.  The extra credit is worth 40 points, 60% on the mathematics and 40% on the aesthetic quality of your project.  All extra credit is due one week before the term closes.

 

The Great Stellated Dodecahedron

Materials: Seventy-five non-flexible drinking straws, fifteen of which have been cut in half (yielding 60 whole straws and 30 half straws, a spool of thread (button or carpet or something as strong). A heavy, straight large eyed needle (preferably blunt-pointed).

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Procedure

          1. Start by threading the needle with a piece of thread about a meter long.

2. Tie three (3) half-straws into a triangle by running the thread through them and knotting snugly and securely.

          3. Add a triangle by tying on two (2) more half-straws.

4. DO the same Łor a third triangle. note: The three triangles have a common vertex at A.

         5. Tie on a fourth triangle so that it shares the        

             A  vertex.

6. Tie a single half-straw between vertex B and C. Note: The A vertex will "pop up*, and the figure will be a pentagonal pyramid.

 

7. Using two half straws add a triangular flap to one side of the base of the pyramid.

8. Do the same for the remaining four sides of the base.

9. Repeat steps 1-6 with the remaining ten (10) half-straws.

 

 

 

9. Repeat steps 1-6 with the remaining ten (10) half-straws.

10. Turn the pyramid In step 9 upside down and tie the vertices of its base to the flaps of the figure in step 8, forming an icosahedron.

            11.Tie three straws (whole straws, you should  now be out of half-straws) to the vertices of one of the triangular faces of  the   icosahedron in step 10, and tie their free ends together to form a triangular pyramid.

 

            12. Do the same for the other nineteen faces of the icosahedron.

            13.Tighten up the loose joints, snip off thread ends, and you are ready to decorate your great                   stellated  dodecahedron with spray paint, glitter, glue, tassels or what have you. 

E-Mail: jholliday@quincy.k12.ma.us