Sometimes it's nice to play with illustrator a bit.
The geometric link of the Dehn complex associated to the trefoil knot embeds into the regular projection.
The infinite trivalent tree with edges metrized as decaying by 1/2 as they get farther away from the root embedded in the unit disk.
Exploring the structure of the dodecahedral graph.
A group acts properly and cocompactly on a simply-connected geodesic metric space if and only if it is finitely presented.
I once spent three weeks kayaking in Northeast Greenland.