A new universality for random sequential deposition of needles

Percolation and jamming phenomena are investigated for random sequential deposition of rectangular needles on d = 2 square lattices. Associated thresholds p(c)(perc) and p(c)(jam) are determined for Various needle sizes. Their ratios p(c)(perc)/p(c)(jam) are found to be a constant 0.62 +/- 0.01 for all sizes. In addition the ratio of jamming thresholds for respectively square blocks and needles is also found to be a constant 0.79 +/- 0.01. These constants exhibit some universal connexion in the geometry of jamming and percolation for both anisotropic shapes (needles versus square lattices) and isotropic shapes (square blocks on square lattices). A universal empirical law is proposed for all three thresholds as a function of alpha.