1. The normal to a surface element is and a missing bond
    will be contained in a unit circle if

    and we can define the sum of all bonds in a surface element for the same bond energy as .
  2. We define the surface tension to be: ,
    where is a surface element and is the bond energy.
  3. The WULFF CONSTRUCTION is analytic for simple Bravais NN cases, and can be done numerically otherwise. It is the minimal shape formed by the planes that have the minimal distance from the origin at each angle, see image at left from Herring, Phys.Rev. (1950)