de Bruijn's Theorem
A box can be packed with a Harmonic Brick 
Iff the box has dimensions 
for some natural numbers 
, 
, 
(i.e., the box is a multiple of the brick).
References
Honsberger, R. Mathematical Gems II. Washington, DC: Math. Assoc. Amer., pp. 69-72, 1976.
- Seifert's Spherical Spiral
- Seifert Surface
- Self-Adjoint Matrix
- Self-Adjoint Operator
- Self-Avoiding Walk
- Self-Conjugate Subgroup
- Self-Descriptive Number
- Self-Homologous Point
- Self Number
- Self-Reciprocating Property
- Self-Recursion
- Selfridge-Hurwitz Residue
- Selfridge's Conjecture
- Self-Similarity
- Self-Transversality Theorem
- Selmer Group
- Semialgebraic Number
- Semianalytic
- Semicircle
- Semicolon Derivative
- Semiconvergent Series
- Semicubical Parabola
- Semiderivative
- Semidirect Product
- Semiflow