The growth of nanoporous alumina on concave and convex aluminum surfaces is studied using small egments. Pore bifurcation and termination cause a stepwise change in the pore number N, as well as the average interpore angle (alpha(p)) over bar as the thickness of the oxide increases. Interpore distances (d) over bar exhibit a sawtooth-shaped graph as a function of pore length, further emphasizing the discrete nature of the pore creation and termination processes. (C) 2011 Elsevier Ltd. All rights reserved.