Movie S5.

A polar liquid flows through a 3mm wide circular chamber including a random lattice of obstacles (highlighted in orange). At small disorder, the obstacles hardly alter the coarsening dynamics of the polar liquids. The spontaneous flows self-organize into a macroscopic vortex over system-spanning scales. Obstacle fraction: Φ_o = 3%. Colloid fraction ρ₀ = 0.08. Colloid diameter: 4.8 μm. Field amplitude: E₀ = 4.5V/μm. Video recorded at 190 fps, played at 25 fps.