  We define and study a three dimensional lattice model which displays a Weyl
semi-metallic phase. This model consists of coupled layers of quantum
(anomalous) Hall insulators. The Weyl semi-metallic phase appears between a
resulting quantum Hall insulating phase and a normal insulating phase. Weyl
fermions in this Weyl semi-metal, similar to Dirac fermions in graphene, have
their lattice pseudo-spin locked to their momenta. We investigate surface
states and Fermi arcs, and their evolution for different phases, by exactly
diagonalizing the lattice model as well as by analyzing their topological
origins.
