void setup(){
  frameRate(100);
  size(500,500);
 smooth();
}
float a = 90;
float s = 100;
float o_s = 100;
int add = 10;

float y = 500;
float x = random(0, 500);

void draw(){
  Circle c = new Circle(y+= 4);
  if (y >= 500){
    y = random(0, 500);
    x = random(0, 500);
  }
}

class Circle {
  float c1;
  Circle (float y){
    rotate(radians(a+=1));
    fill (random(0, 255), random(0, 255), random(0, 255));
    ellipse(x, y, s+=add, o_s);    
    if (s >= 200){
      add = -10;
    } else if (s <= 0){
      add = 10;
    }
  }
}