Keywords: 1planar-K2222.svg 1-planar drawing of the hyperoctahedral graph K<sub>2 2 2 2</sub> Each of its eight vertices is adjacent to the six vertices with different colors from it but not to the one other vertex with the same color 2013-01-19 12 34 36 own David Eppstein cc-zero Files by User David Eppstein from en wikipedia Graphs with 8 vertices Graph coloring; vertex |