  We describe explicitly the correspondence of Edge between the set of planes
contained in the Fermat cubic 4-fold in characteristic 2, and the set of
lattice points T of the Leech lattice such that OABT is a regular tetrahedron,
where O is the origin of the Leech lattice, and A and B are fixed points of the
Leech lattice such that OAB is a regular triangle of edge length 2. Using this
description, we present Conway's isomorphism from PSU(6,4) to \cdot 222 in
terms of matrices.
