Granular materials, those made up of individual pieces, whether grains of sand or coffee beans or pebbles, are the most abundant form of solid matter on Earth. The way these materials move and react to external forces can determine when landslides or earthquakes happen, as well as more mundane events such as how cereal gets clogged coming out of the box. Yet, analyzing the way these flow events take place and what determines their outcomes has been a real challenge, and most research has been confined to two-dimensional experiments that…
