(Dedicated to the memory of Ragnar-Olaf Buchweitz)
I promise that you will hear some of the following words in this talk: platonic solids, Egyptian fractions, Dynkin diagrams, subgroups of $\mathrm{SL}(2,\mathbb{C})$, Kleinian singularities, Gabriel's theorem on quiver representations, its commutative version due to Buchweitz-Greuel-Schreyer, McKay correspondence, preprojective algebra, maximal Cohen-Macaulay modules, simple singularities. I do not promise that you will hear all of these words but I will do my best. No background is necessary.