[[File:cusp catastrophe.png|thumb|upright=1.5|Diagram of cusp catastrophe, showing curves (brown, red) of ''x'' satisfying ''dV''/''dx'' = ''0'' for parameters (''a'',''b''), drawn for parameter ''b'' continuously varied, for several values of parameter ''a''. | [[File:cusp catastrophe.png|thumb|upright=1.5|Diagram of cusp catastrophe, showing curves (brown, red) of ''x'' satisfying ''dV''/''dx'' = ''0'' for parameters (''a'',''b''), drawn for parameter ''b'' continuously varied, for several values of parameter ''a''. |