class Node{
  Vec3D position;
  ArrayList neighbors;

  Node(){
    position=new Vec3D();
    neighbors= new ArrayList();

  }

  Node(Vec3D position){
    this.position=new Vec3D(position);
    this.neighbors= new ArrayList();

  }

  Node chooseNeighbor(){
    int n = neighbors.size();
    return (Node)neighbors.get(constrain((int)random(n),0,n-1));
    
    
    }
   
   void add(Node neighbor){
     neighbors.add(neighbor);
     }


}