One relatively recent branch of mathematics that you may encounter at university is called graph theory. This branch of mathematics has nothing to do with bar graphs, pie charts, etc., but is instead concerned with the study of graphical networks (graphs), which look like “connect-the-dots” puzzles—the dots are called vertices, and the lines connecting them are called edges.
One pioneer in the field of graph theory is Bill Tutte, and you can read an article about him and his role in the Second World War here.