Astroid : http://www.mathcurve.com/surfaces/astroidal/astroidal.shtml[br]Berlingot : http://www.mathcurve.com/surfaces/berlingot/berlingot.shtml[br]Bohemian dome : http://www.mathcurve.com/surfaces/boheme/boheme.shtml[br]Bonnet croisé ( Cross-cap) : http://www.mathcurve.com/surfaces/bonnetcroise/bonnetcroise.shtml[br]Romaine : http://www.mathcurve.com/surfaces/romaine/romaine.shtml