A Unit-Distance Graph Coloured

The Prompt

Construct and colour a unit-distance graph of your own design — at least 15 vertices — and determine its chromatic number. Then attempt to extend the graph to force a higher chromatic number. Compare your construction to the Moser spindle (7 vertices, chromatic number 4) and, if possible, to de Grey's 5-chromatic graph. Record the graph (vertex coordinates and edges), the colouring, and what the construction process revealed about why raising the lower bound is difficult.

Completion Criteria

The graph (coordinates, edges, and colouring), its chromatic number, and a one-paragraph reflection on the difficulty of raising the bound.

Students who have attested

No Students have attested this quest yet. Be the first.