Hello, I've been trying to figure out how to keep a flock in a specific shape, or formation, while moving & steering it in the most natural way.

I have a flock that follows a non-Boid leader, now I need a way to form Boids into shapes, like a straw, oval, or a rectangle. I've tried a point formation, and had Boids arrive on those points, but couldn't figure out how to steer it in a desirable manner, aside from sliding left to right.

Are there any known techniques for doing this?