  The mean-centered cuboidal (or m.c.c.) lattice is known to be the optimal
packing and covering among all isodual three-dimensional lattices. In this note
we show that it is also the best quantizer. It thus joins the isodual lattices
Z, A_2 and (presumably) D_4, E_8 and the Leech lattice in being simultaneously
optimal with respect to all three criteria.
