A combination of the above plane polygonal pieces such that the Edges are coincident. There are 13 convex tangrams (where a ``convex tangram'' is a set of tangram pieces arranged into a Convex Polygon).

**References**

Cundy, H. and Rollett, A. *Mathematical Models, 3rd ed.* Stradbroke, England: Tarquin Pub., pp. 19-20, 1989.

Gardner, M. ``Tangrams, Parts 1 and 2.'' Ch. 3-4 in *Time Travel and Other Mathematical Bewilderments.*
New York: W. H. Freeman, 1988.

Johnston, S. *Fun with Tangrams Kit: 120 Puzzles with Two Complete Sets of Tangram Pieces.* New York: Dover, 1977.

Pappas, T. ``Tangram Puzzle.'' *The Joy of Mathematics.* San Carlos, CA: Wide World Publ./Tetra, p. 212, 1989.

© 1996-9

1999-05-26