Fig. 4. Fiber network model:

a, Fiber network simulations (green) with contractile cells modelled as force dipoles (top, 2 point forces of 5000 pN, distance approx. 125 px) or quadrupoles (bottom, 4 point of 5000 pN, distance approx. 125 px). Contractility refers to the sum of individual point forces. b, Angular distribution of fiber orientation around a dipole or quadrupole (light green, cones bin width 5°), or for a cell-free network (gray). c, Fiber networks (black/white) and resulting orientation fields (blue/red) for a series of differently contractile quadrupoles. The mean fiber orientation (d, left) and fiber intensity close to the cell surface (d, right) increases with contractility similarly for both dipoles and quandrupoles. e) Fiber orientation (left) and fiber intensity (right) as a function of the distance from the outer cell contour, for dipoles (gray) and quadrupoles (green) and different contractilities.