Compress soft disks slowly. At φ_J ≈ 0.64 (random close packing), the system jams: pressure diverges, contact network percolates, and the system becomes rigid. Watch the force network emerge.
The jamming transition (Liu & Nagel 1998): frictionless soft spheres jam at φ_J≈0.64 (2D). At jamming: pressure P~(φ-φ_J)^1, contact number Z-Z_c~(φ-φ_J)^0.5, bulk modulus discontinuous. The jam point J is a critical point governing rigidity in foams, granular matter, and dense suspensions.