  Dust configurations are the simplest models for astrophysical objects. Here
we examine the gravitational collapse of an infinite cylinder of dust and give
an analytic interior solution. Surprisingly, starting with a cylindrically
symmetric ansatz one arrives at a 3-space with constant curvature, i.e. the
resulting metric describes a piece of the Friedman interior of the
Oppenheimer-Snyder collapse. Indeed, by introducing double polar coordinates, a
3-space of constant curvature can be interpreted as a cylindrically symmetric
space as well. This result shows afresh that topology is not fixed by the
Einstein equations.
