int numCircle = 150; 
Circle[] circles = new Circle[numCircle]; 
 
void setup() 
{ 
  size(400, 400); 
  frameRate(20); 
  for(int i=0; i<numCircle; i++) { 
    circles[i] = new Circle(random(width), 
	      (float)height/(float)numCircle * i, 
	      int(random(2, 6))*10, random(-0.25, 0.25), 
	      random(-0.25, 0.25), i); 
  } 
  ellipseMode(CENTER_RADIUS); 
 
} 
 
 
void draw() 
{ 
  background(255); 
  stroke(0); 
  
 
  for(int i=0; i<numCircle; i++) { 
    circles[i].update(); 
  } 
  for(int i=0; i<numCircle; i++) { 
    circles[i].move(); 
  } 
  for(int i=0; i<numCircle; i++) { 
    circles[i].makepoint(); 
  } 
  noFill();
  filter(BLUR, 2); 
} 


 
 
class Circle 
{ 
  float x, y, r, r2, sp, ysp, s; 
  int id; 
 
  Circle( float px, float py, float pr, float psp, float pysp, int pid ) { 
    x = px; 
    y = py; 
    r = pr; 
    r2 = r*r; 
    id = pid; 
    sp = psp; 
    ysp = pysp; 
    s = random(5,10);
  }   
  void update() { 
    for(int i=0; i<numCircle; i++) { 
      if(i != id) { 
        intersect( this, circles[i] ); 
      } 
    } 
  }   
  void makepoint() { 
     stroke(255);
    fill(0,100); 
    ellipse(x, y, s, s);
    fill (255,0,0);
   ellipse (x+1, y-1, 2,2); 
   
  }   
  void move() { 
    x += sp; 
    y += ysp; 
    if(sp > 0) { 
      if(x > width+r) { 
        x = -r; 
      }   
    } else { 
      if(x < -r) { 
        x = width+r; 
      } 
    } 
    if(ysp > 0) { 
      if(y > height+r) { 
        y = -r; 
      } 
    } else { 
      if(y < -r) { 
        y = height+r; 
      } 
    } 
  } 
} 
 
void intersect( Circle cA, Circle cB ) 
{ 
  float dx = cA.x - cB.x; 
  float dy = cA.y - cB.y; 
  float d2 = dx*dx + dy*dy; 
  float d = sqrt( d2 ); 
 
  if ( d>cA.r+cB.r || d<abs(cA.r-cB.r) ) { 
    return; // no solution 
  } 
  
  //  calculate the two intersections between the two circles cA and cB, //
  //  whose coordinates are (paX, paY) and (pbX, pbY), respectively.     //
  
}