Angular Structure of Lacunarity, and the Renormalisation Group
  We formulate the angular structure of Lacunarity in fractals, in terms of a symmetry reduction of the three point correlation function. This provides a rich probe of universality, and first measurements yield new evidence in support of the equivalence between self-avoiding walks and percolation perimeters in two dimensions.   We argue the Lacunarity reveals much of the Renormalisation Group in real space. This is supported by exact calculations for Random Walks and measured data for percolation clusters and SAW's. Relationships follow between exponents governing inwards and outwards propagating perturbations, and we also find a very general test for the contribution of long range interactions. 
RC Ball, G Caldarelli, A Flammini