Keywords: 18-vertex zero-symmetric graph.svg zero-symmetric graph a cubic graph whose vertices are symmetric but whose edges fall into three different symmetry classes Redrawn in a different style from Fig 1 1 of Coxeter Harold Scott MacDonald; Frucht Roberto; Powers David L 1981 Zero-symmetric graphs Academic Press Inc Harcourt Brace Jovanovich Publishers New York-London ISBN 0-12-194580-4 MR 658666 p 5 2015-01-10 own David Eppstein other versions cc-zero Uploaded with UploadWizard Graphs with 18 vertices 9-fold rotational symmetry |