// Number of spots
int numSpots = 12;
// Declare and create an array of spots
Spot[] spots = new Spot[numSpots];  
String title = "Yay spots!";

void setup(){
  size(200, 200);  
  smooth();
  noStroke();
  for (int i = 0; i < spots.length; i++) {
    float x = 10 + i*16;
    float rate = 0.5 + i*0.05;
    color c = color(random(255), random(255), random(255));
    spots[i] = new Spot(x, 50, 10+random(20), rate, c);
  }
}

void draw(){
  background(0);
  for(int i =0; i < spots.length; i++){
     spots[i].move();
     spots[i].changeColor();
     spots[i].diameter = 5+random(20);
     spots[i].display();
  }
  
}

class Spot {
  float x;           // X-coordinate
  float y;           // Y-coordinate
  float diameter;    // Diameter of circle
  float speed;       // Distance moved each frame
  int direction = 1; // Direction (1 is down; -1 is up)
  color col;

  Spot(float xpos, float ypos, float dia, float s, color c){
    x = xpos;
    y = ypos;
    diameter = dia;
    speed = s; 
    col = c; 
    
  }

  void display() {
    fill(col);
    ellipse(x, y, diameter, diameter); 
  }

  void move(){
    y += (speed * direction);
    if((y > (height - diameter/2)) || (y < diameter/2)){
      direction *= -1;
    }
  }

  // The disappear() method does not do anything until you add code inside of the curl braces {}.
  void disappear(){}
  
  void changeColor(){
     col = color(random(255), random(255), random(255));
  }
}