Fig. 2: Schematic illustration of the spontaneous bent shape of Hydra fragments.
a Schematic illustration for the spontaneous bent shape of Hydra fragments driven by uniformly contracting supracellular actomyosin bundles. The contour length, width, and total thickness of the fragments are denoted by ℓc, b, and h, respectively. b A schematic bent-shape diagram of Hydra plates with different anisotropy in actomyosin contractility (measured by c2/c1) and in elasticity (measured by \({E}_{2}^{(k)}/{E}_{1}^{(k)}\) in each k = 1, m, 2 lamina layer). Here ci characterizes the contractility of the two sets of perpendicular supracellular bundles; \({E}_{1}^{(k)}\) and \({E}_{2}^{(k)}\) are the two principal Young’s moduli of each (k = 1, m, 2) orthotropic lamina layer.
