  The type D Kasner vacuum solution of general relativity is reviewed,
highlighting the little-known, intriguing property that it can describe both an
anisotropic cosmology and the spacetime deep within a black hole, these two
descriptions linked by a reversal of the time-ordering of the solution. The
flexible nature of solutions of Einstein's equations is emphasised, and a brief
discussion of the arrow of time in modern physics is presented.
