  Although quantum Monte Carlo is, in principal, an exact method for solving
the Schroedinger equation, it is well-known that systems of Fermions still pose
a challenge. Thus far all solutions to the "sign problem" remain inefficient
(or wrong). The fixed-node approach, however, is efficient, and in many
situations remains the best approach. If only we could find the exact nodes, or
at least a systematic way to improve the nodes, we would, in effect, bypass the
sign problem. Unfortunately, very little is known about wave function nodes,
and a systematic study has never been attempted, despite the obvious
consequences for improving quantum simulations that such knowledge might
generate. In this paper we study the nodal surfaces of simple atomic systems.
