  We present a theoretical and experimental analysis of the elliptical-like
orbits of a marble rolling on a warped spandex fabric. We arrive at an
expression describing the angular separation between successive apocenters, or
equivalently successive pericenters, in both the small and large slope regimes.
We find that a minimal angular separation of approximately 197 degrees is
predicted for orbits with small radial distances when the surface is void of a
central mass. We then show that for small radii and large central masses, when
the orbiting marble is deep within the well, the angular separation between
successive apocenters transitions to values greater than 360 degrees. We lastly
compare these expressions to those describing elliptical-like orbits about a
static, spherically symmetric massive object in the presence of a constant
vacuum energy, as described by general relativity.
