The House of Graphs is a database of interesting graphs (not charts, plots or diagrams – but proper graphs with nodes and arcs). Searchable by a huge range of invariants, either for a specific value, or a range, or just that having an interesting value – plus, there’s a funky search tool where you can draw the graph using a nice input tool, and search that way. It’s basically the best website I’ve ever seen.
This is part of the Aperiodical Advent Calendar. We’ll be posting a new surprise for you each morning until Christmas!