  The Teichmuller unipotent flow can be defined concretely on certain moduli
spaces of singular flat surfaces by shearing polygonal presentations of the
surfaces. Thurston's earthquake flow on moduli spaces of hyperbolic surfaces is
more mysterious. Both flows have deep and important connections to other areas
of mathematics.
  In this expository survey we give a geometric account of the main ideas
behind Mirzakhani's theorem relating these two flows. Our presentation avoids
some technical prerequisites that featured in the original more analytic
presentation.
