The impressive complexity in the Nautilus pompilius shell
  The complexity of the Nautilus pompilius shell is analyzed in terms of its fractal dimension and its equiangular spiral form. Our findings assert that the shell is fractal from its birth and that its growth is dictated by a self-similar criterion (we obtain the fractal dimension of the shell as a function of time). The variables that have been used for the analysis show an exponential dependence on the number of chambers/age of the cephalopod, a property inherited from its form. 
A. A. Castrejon Pita, J. R. Castrejon Pita, A. Sarmiento Galan, and R.   Castrejon Garcia