Figure 1
APS/Alan Stonebraker

Figure 1: Schematic representation of the sandpile model used by Noël et al. When one grain falls on top of a pile with three grains (a), the pile becomes unstable and topples. While toppling, all grains in the pile are evenly distributed among the four neighbors (b). The toppling cascades further as one neighboring pile becomes unstable (four grains) and also topples (c).