  Motivated by recent progress in epitaxial growth of proximity structures of
s-wave superconductors (S) and spin-active materials (M), we show that the
periodic structure of S and M can behave effectively as a superconductor with
pairs of point nodes, near which the low energy excitations are Weyl fermions.
A simple toy model, where M is described by a Kronig-Penney potential with both
spin-orbit coupling and exchange field, is proposed and solved to obtain the
phase diagram of the nodal structure, the spin texture of the Weyl fermions, as
well as the zero energy surface states in the form of open Fermi lines ("Fermi
arcs"). Going beyond the simple model, a lattice model with alternating layers
of S and magnetic $Z_2$ topological insulators (M) is solved. The calculated
spectrum confirms previous prediction of Weyl nodes based on tunneling
Hamiltonian of Dirac electrons. Our results provide further evidence that
periodic structures of S and M are well suited for engineering gapless
topological superconductors.
