A flocking swarm of procedural butterflies drifts over a sunlit flower meadow, demonstrating the classic "boids" algorithm (separation, alignment, cohesion) used to model emergent group behavior in animals. Each of the 60 butterflies is a small THREE.Group with two hinged wing pivots flapped by a sine wave, and every frame runs an O(n²) neighbor scan to steer velocities toward nearby flockmates while avoiding collisions.