Percolation and roughness in ballistic deposition of complex shapes
  This paper investigates how the measurement of geometrical features of structures obtained from ballistic deposition of objects with complex shapes, particularly neuronal cells, can be used for characterization and analysis of the shapes involved. The experiments were performed on both synthetic (prototypes) and natural shapes. Two measurements were considered, namely the surface roughness and the critical percolation density, with the former providing better discrimination of shape characteristics for alpha and beta neuronal cells of cat retina. 
Linder C. da Silva, Marconi S. Barbosa, Osvaldo N. Oliveira Jr. and   Luciano da F. Costa