static void forceBasedLayout(CirclesAndLines cal, final Canvas canvas) {
  awtEvery(canvas, r {
    L<Circle> circles = cal.circles;
    int n = l(circles);
    
    new BitSet bs;
    for (Line l : cal.lines)
      bs.set(circles.indexOf(l.a)*n+circles.indexOf(l.b));
      
    for (int i = 0; i < n; i++) {
      Circle a = circles.get(i);
      for (int j = 0; j < n; j++)
        if (i != j) {
          Circle b = circles.get(j);
          bool connected = bs.get(i*n+j);
          if (connected)
            forceBasedLayout_attract(a, b);
          else
            forceBasedLayout_repel(a, b);
        }
    showCAL2(cal, cal, canvas);
  }
}

static Vector forceBasedLayout_repulsionForce(Circle a, Circle b) {
  po proximity = max(distance(a.x, a.y, b.x, b.y), 0.1);
  double force = -REPULSION_CONSTANT / sqr(proximity);
  double angle = GetBearingAngle(x.Location, y.Location);
  return doublePtFromAngle(force, angle);
}

svoid forceBasedLayout_attract(Circle a, Circle b) {
  double distance = sqr(b.x-a.x)+sqr(b.y-a.y);
  double desiredDistance = 0.1;
  double distanceDelta = desiredDistance
  
  double dx = (b.x-a.x)*strength, dy = (b.y-a.y)*strength;
  a.x += dx*
}