Roger Penrose is credited with identifying nontrivial cohomology as a basic requirement for a certain class of optical illusion present in the work of artist M.C. Escher. The so-called Penrose Triangle has since become an emblem for cohomology. It captures, in a discrete way, the kind of rotating vector fields whose singularities allow for the nonexistence of an antiderivative and stand as a primary motivating example for de Rham cohomogy in the first place. However, in many ways, the discrete theory is much older. In this talk, I will explore some appearances of discrete de Rham cohomology theory in the 1860’s, the 1960’s, and their impact in later problems in discrete and computational geometry. Then, I will argue that discrete differential forms are a powerful tool for geometric graph algorithms.