Baguenaudier
A Puzzle involving disentangling a set of rings from a looped double rod (also called Chinese Rings). Theminimum number of moves needed for 
rings is
By simultaneously moving the two end rings, the number of moves can be reduced to
The solution of the baguenaudier is intimately related to the theory of Gray Codes.
References
Dubrovsky, V. ``Nesting Puzzles, Part II: Chinese Rings Produce a Chinese Monster.'' Quantum 6, 61-65 (Mar.) and 58-59 (Apr.), 1996. Gardner, M. ``The Binary Gray Code.'' In Knotted Doughnuts and Other Mathematical Entertainments. New York: W. H. Freeman, pp. 15-17, 1986. Kraitchik, M. ``Chinese Rings.'' §3.12.3 in Mathematical Recreations. New York: W. W. Norton, pp. 89-91, 1942. Steinhaus, H. Mathematical Snapshots, 3rd American ed. New York: Oxford University Press, p. 268, 1983.
- Standard Tori
- Stanley's Theorem
- Star
- Star Figure
- Star (Fixed Point)
- Star Fractal
- Star Graph
- Star Number
- Star of David
- Star of Goliath
- Star of Lakshmi
- Star Polygon
- Star Polyhedron
- Starr Rose
- State Space
- Stationary Point
- Stationary Tangent
- Stationary Value
- Statistic
- Statistical Test
- Statistics
- Staudt-Clausen Theorem
- Steenrod Algebra
- Steenrod-Eilenberg Axioms
- Steenrod's Realization Problem