.................................................................................................................................... II List of Publications ................................................................................................................... III List of Figures ...........................................................................................................

Introduction: Nature presents abundant examples of closed curves that may be considered as some sort of deformed ellipses. Gielis (2003) invented a superformula to parameterize such shapes.

Article history: Received 23 July 2013 Received in revised form 13 April 2014 Accepted 5 May 2014 Available online 15 May 2014 Communicated by A. Skowron