  The S-matrix for planar N = 4 super Yang-Mills theory can be computed as the
correlation function for a holomorphic polygonal Wilson loop in twistor space.
In an axial gauge, this leads to the construction of the all-loop integrand via
MHV diagrams in twistor space. We show that at MHV, this formulation leads
directly to expressions for loop integrands in d log form; i.e., the integrand
is a product of exterior derivatives of logarithms of rational functions. For
higher MHV degree, it is in d log form multiplied by delta functions. The
parameters appearing in the d log form arise geometrically as the coordinates
of insertion points of propagators on the holomorphic Wilson loop or on MHV
vertices. We discuss a number of examples at one and two loops and give a
preliminary discussion of the evaluation of the 1-loop MHV amplitude.
