Rafi Bistritzer and Allan H. MacDonald, at the University of Texas at Austin, publish in 2011 "Moiré bands in twisted double-layer graphene" (PNAS), a continuum model predicting the electronic behavior of two graphene sheets stacked and rotated relative to each other by a small angle. Superimposing two hexagonal carbon lattices with a slight relative twist generates a geometric interference pattern (a moiré pattern) that modulates the rate at which electrons can hop from one layer to the other. Bistritzer and MacDonald calculate that, for a discrete set of twist angles — the first around 1.05° — this tunneling rate vanishes completely: the electronic bands, normally dispersive, become almost entirely flat ("flat bands"), and the density of states at the Dirac point is enormously amplified. The model precisely predicts the exact angle at which the phenomenon should occur, but in 2011 it remains a theory on paper with no experimental data confirming it and no application making it relevant. Seven years later, in 2018, Pablo Jarillo-Herrero, at MIT, together with his doctoral student Yuan Cao, experimentally fabricates exactly the device the theory predicted: two graphene sheets stacked and rotated 1.1°, the "magic angle". At sufficiently low temperatures, the material — which under normal conditions is a simple carbon conductor — exhibits unconventional superconductivity, controllable via an electric field that adjusts the number of injected electrons. None of the three pieces alone constitutes a paradigm shift: the 2011 theory was an unverified prediction; the isolated material (graphene, 2004) was a substrate with no such exceptional quantum behavior; the 2018 experiment would have been inexplicable without the model that predicted exactly where to look. Together, the three pieces close a complete circle — theory proposing never-before-seen rules, an experiment demonstrating that those rules govern the real world, and an unexpected physical phenomenon (superconductivity) opening an entirely new field of research — and give rise to "twistronics": electronics based on the twist angle between layers of 2D materials. By adjusting the twist angle in fractions of a degree, it is possible to induce spontaneous magnetism, unusual topological quantum states, or superconductivity in the same material, without ever altering its chemical composition.