import { ParticleForce } from '../universe';
declare function blackHole(blackHoleX: number, blackHoleY: number, strength?: number): ParticleForce;
declare function disturbance(x: number, y: number, strength?: number): ParticleForce;
declare function entropy(n: number): ParticleForce;
declare const friction: ParticleForce;
export { blackHole, disturbance, entropy, friction };