ArrayList Bricks = new ArrayList();
Background bg;
 
class Brick{
 
  float x, y, w, h;
  float r, g, b, a;
  float life, birth;
  float weight;
  
  Brick() {
    x = random(0, width);
    y = random(0, height);
    w = random(1,width/2);
    h = random(1,height/2);
    weight = (w * h) / 1000;
    if(weight < 5 )
      weight = 5;
 
    r = random(0,255);
    g = random(0,255);
    b = random(0,255);
    a = random(0,255);
    birth = life = random(500, 1000);
  }
  void updatePos() {
    float dx = mouseX - x - (w/2);
    if(abs(dx) > 1) {
      x = x + dx/weight;
    }
  
  float dy = mouseY - y - (h/2);
  if(abs(dy) > 1) {
    y = y + dy/weight;
  }
    
    
   // x = x - (w/2);
   // y = y - (h/2);
  }
 
  void update() {
    --life;
  }
 
  void render() {
 
    strokeWeight(5);
    stroke(0, (life/birth)*255);
    fill(r,g,b, (life/birth)*a);
    rect(x, y, w, h);
  }
 
  boolean isDead() {
    if( a <= 0 )
      return true;
    return false;
  }
}
 
class Background {
  float r, g, b;
  float step;
 
  Background() {
    r = random(200, 255);
    g = random(200, 255);
    b = random(200, 255);
    step = 2;  
  }
 
  void update() {
    r += random(-step, step);
    g += random(-step, step);
    b += random(-step, step);
  }
  void render() {
    background(r, g, b);
  }
}
 
void setup()
{
  size(400, 400);
  frameRate(30);
  Bricks.add(new Brick());
  bg = new Background();
}
 
void draw()
{
  // Render our background
  bg.render();
 
  // Render our bricks
  for(int i = 0; i<Bricks.size()-1; ++i)
  {
    Brick temp = (Brick)Bricks.get(i);
    temp.render();
    temp.update();
  }
 
  // Remove any dead bricks, separate from above loop because
  // it caused flashing when the array was compacted.
  for(int i = 0; i<Bricks.size()-1; ++i)
  {
    Brick temp = (Brick)Bricks.get(i);
    if(temp.isDead()) {
      Bricks.remove(i);
    }
  }
 
  // Render our brick above the mouse.
  Brick temp = (Brick)Bricks.get(Bricks.size()-1);
  temp.updatePos();
  temp.render();
}
 
void mouseMoved()
{
   bg.update();
}
 
void mousePressed()
{
  Bricks.add(new Brick());
}