  Higher-rank graphs are, as the name suggests, higher-dimensional analogues of
directed graphs which we will define using category theory. The whole idea of
my project was to construct what we call a Baumslag-Solitar graph, a
higher-rank graph. They're too abstract an idea to picture, but in building
Baumslag-Solitar graphs through coloured graphs, we are able to do so. I
modelled my work on constructing Baumslag-Solitar graphs off Hazlewood,
Raeburn, Sims, and Webster's Remarks on some fundamental results about
higher-rank graphs and their $C^*$-algebras. This was a novel approach in
understanding the generalisation of directed graphs.
