We consider maximally supersymmetric SU(N) Yang--Mills theory in Euclidean
signature compactified on a flat two-dimensional torus with anti-periodic
(`thermal') fermion boundary conditions imposed on one cycle. At large N,
holography predicts that this theory describes certain black hole solutions in
Type IIA and IIB supergravity, and we use lattice gauge theory to test this.
Unlike the one-dimensional quantum mechanics case where there is only the
dimensionless temperature to vary, here we emphasize there are two more
parameters which determine the shape of the flat torus. While a rectangular
Euclidean torus yields a thermal interpretation, allowing for skewed tori
modifies the holographic dual black hole predictions and results in another
direction to test holography. Our lattice calculations are based on a
supersymmetric formulation naturally adapted to a particular skewing. Using
this we perform simulations up to N=16 with several lattice spacings for both
skewed and rectangular tori. We observe the two expected black hole phases with
their predicted behavior, with a transition between them that is consistent
with the gravity prediction based on the Gregory--Laflamme transition.