Any closed 3-manifold M may
be thought of as a union of 3-celIs. Any covering space of M is made up of copies of
these 3-cells with boundaries locally identified as in M. Covers of M may be built by
piecing together these balls. This paper develops a method to piece together
the universal cover of manifolds obtained from the 3-sphere by surgery on
a class of pretzel knots in such a way that the cover can be shown to be
R3.