Polyhex
An analog of the Polyominoes and Polyiamonds in which collections of regularhexagons are arranged with adjacent sides. They are also called Hexes and Hexas. The number of polyhexes of 
hexagons are 1, 1, 3, 7, 22, 82, 333, 1448, 6572, 30490, 143552, 683101, ...(Sloane's A000228). For the4-hexes (tetrahexes), the possible arrangements are known as the Bee, Bar, Pistol,Propeller, Worm, Arch, and Wave.
References
Gardner, M. ``Polyhexes and Polyaboloes.'' Ch. 11 in Mathematical Magic Show: More Puzzles, Games, Diversions, Illusions and Other Mathematical Sleight-of-Mind from Scientific American. New York: Vintage, pp. 146-159, 1978. Gardner, M. ``Tiling with Polyominoes, Polyiamonds, and Polyhexes.'' Ch. 14 in Time Travel and Other Mathematical Bewilderments. New York: W. H. Freeman, pp. 175-187, 1988. Golomb, S. W. Polyominoes: Puzzles, Patterns, Problems, and Packings, 2nd ed. Princeton, NJ: Princeton University Press, pp. 92-93, 1994. Sloane, N. J. A. SequenceA000228/M2682in ``An On-Line Version of the Encyclopedia of Integer Sequences.''http://www.research.att.com/~njas/sequences/eisonline.html and Sloane, N. J. A. and Plouffe, S.The Encyclopedia of Integer Sequences. San Diego: Academic Press, 1995. von Seggern, D. CRC Standard Curves and Surfaces. Boca Raton, FL: CRC Press, pp. 342-343, 1993.
- Spherical Geometry
- Spherical Hankel Function of the First Kind
- Spherical Hankel Function of the Second Kind
- Spherical Harmonic
- Spherical Harmonic Addition Theorem
- Spherical Harmonic Closure Relations
- Spherical Harmonic Tensor
- Spherical Helix
- Spherical Point System
- Spherical Polygon
- Spherical Ring
- Spherical Sector
- Spherical Segment
- Spherical Shell
- Spherical Spiral
- Spherical Symmetry
- Spherical Tessellation
- Spherical Triangle
- Spherical Trigonometry
- Spherical Vector Harmonic
- Spheroid
- Spheroidal Harmonic
- Spheroidal Wavefunction
- Sphinx
- Spider and Fly Problem