### Project 8.5

Construct models for the regular polyhedra.

*References:
*

**H.S.M. Coxeter**,

*Introduction to Geometry*(New York: Wiley, 1961).

**Jean Pederson**, “Plaited Platonic Puzzles,” *Two-Year College Mathematics Journal,* Fall 1973, pp. 23-27.

**Max Sobel** and **Evan Maletsky**, *Teaching Mathematics: A Sourcebook* (Englewood Cliffs, N.J.: Prentice-Hall, 1975), pp. 173-184.

**Charles W. Trigg**, “Collapsible Models of the Regular Octahedron,” *The Mathematics Teacher,* October 1972, pp. 530-533.

### Project 8.6

What solids occur in nature? Find examples of each of the five regular solids. For example, the skeletons of marine animals called radiolaria show each of these forms.

*References:
*

**David Bergamini**,

*Mathematics*(New York: Time, Inc., Life Science Library, 1963), Chapter 4.

**Juithlynee Carson**, “Fibonacci Numbers and Pineapple Phyllotaxy,” *Two-Year College Mathematics Journal,* June 1978, pp. 132-136.

**James Newman**, *The World of Mathematics* (New York: Simon and Schuster, 1956). “Crystals and the Future of Physics,” pp. 871-881, “On Being the Right Size,” pp. 952-957, and “The Soap Bubble,” pp. 891-900.

*Radiolaria:*

**http://www.ucmp.berkeley.edu/protista/radiolaria/rads.html**

### Project 8.7

What is a Menger sponge, and what is interesting about this figure?