Mathematician Ludwig Schläfli talks about objects that live in the fourth dimension…
M.C. Escher talks about the adventures of two-dimensional creatures trying to imagine what three-dimensional objects look like.
Hipparchus explains how two numbers can describe the position of a point on a sphere.
He then explains stereographic projection: how can one draw a picture of the Earth on a piece of paper?
How to predict and model the spread of epidemics.
The SIR model is one of the simplest disease models we have to explain the spread of a virus through a population.