Fig. 2.

Schematic representation of the model. (a) Each cell is a polygon obtained by the Voronoi tessellation of initially random cell positions r_i, characterized by the area A_i and the perimeter P_i of the polygon. The cell experiences a force F_i = −∇E due to its neighbors and an internal propulsive force f_sⁱ along the direction n_i of its polarization (Eq. 2). (b) An active orientation mechanism reorients each cell’s propulsive force towards its migration velocity over a characteristic response time τ = J⁻¹ (Eq. 3).