Crystalline surface evolving by mean curvature under a cubic anisotropy.
The Wulff shape describing the anisotropy is the cube of side 2 centered
at the origin.

<p>

<ul>
<li><a href="fig_divanoini.jpg">Initial surface</a>, rendered using
PovRay.

<li><a href="fig_divano.jpg">Exact</a> solution at times 0.011,
0.014, 0.0155 (actually obtained by solving a system of ODEs 
obtained using the crystalline evolution law of J. Taylor).
Rendered using PovRay.

<li><a href="treval.jpg">Approximate</a> solution at times 0.011,
0.014, 0.017, obtained by using the Allen-Cahn approximation.
Rendered using Geomview.

</ul>