class Dot {
    
    int x, y, oldY, oldX;
    int r, g, b;
    
    Dot (int x, int y) {
      this.x = x;
      this.oldX = x;
      this.y = y;
      this.oldY = y;
      this.r = (int) random(0,255);
      this.g = (int) random(0,255);
      this.b = (int) random(0,255);
    }