φ that breathes its preferred area a₀ = 1 + α·sin φ;
cells move by overdamped descent of the shape energy. Raise the coupling
J to synchronize the phases and watch the ±1
topological defects of the phase field annihilate.
E = Σ (aᵢ−a₀ᵢ)² + ξ(pᵢ−p₀ᵢ)²; overdamped motion
ṙᵢ = μFᵢ with analytic Voronoi forces; phases by Kuramoto on the
Voronoi graph. Forward Euler; defects = ±1 phase winding around Delaunay
triangles. The rigidity transition sits near p₀ ≈ 3.81;
synchronization near J* ≈ 0.06.