Figure 3.

Noise response. Tension error grows as mean angular noise, of the amounts indicated in angular degrees, is introduced into the averaged dihedral angles. The standard error and residual behave similarly, as does the tension error in a 20-cell epithelium analysed using CellFIT-2D [36]. The standard errors and residuals associated with murine embryo analyses (figure 4b and c) are shown as boxes along their corresponding curves, and they indicate, respectively, equivalent angular noise in the averaged dihedral angles of 6–7% and 2–3%. Tension errors can in turn be deduced from these noise levels to be no greater than 7% (see supplementary text).