Fig 5 -

(A) Schematic of perturbations to the x–component of the initial position x_i of a single vertex relative to a putative four-fold coordinated vertex on the boundary. The green line represents a perfect four-fold vertex where x_i is zero, the blue represents a coordinate that has a positive x_i towards the interface and the red represents a vertex that is further from the interface x_i negative. (B) Analytic restoring force (Eq 7) due to the interfacial tension alone due to the perturbations of vertices on the interface. The solid lines represent intial perturbations of the moving cell’s vertex a distance x_i = {−10⁻⁴, 0, 10⁻⁵, 10⁻⁴, 10⁻³} colored {red, green, dark blue, blue, cyan} respectively with y_i = 1. The dashed blue line represents a perturbation parallel to the interface such that {x_i, y_i} = {10⁻⁴, 1.1}. (C-E) Schematic diagrams of how the larger-scale cellular structure changes when a nearly four-fold coordinated vertex is perturbed as shown in (A).