Keller conjectured that tiling an -D space with -D Hypercubes of equal size yields an arrangement in which at least two hypercubes have an entire -D ``side'' in common. The Conjecture has been proven true for to 6, but disproven for .

**References**

Cipra, B. ``If You Can't See It, Don't Believe It.'' *Science* **259**, 26-27, 1993.

Cipra, B. *What's Happening in the Mathematical Sciences, Vol. 1.* Providence, RI: Amer. Math. Soc., pp. 24, 1993.

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1999-05-26