int numStars = 250 ;
Star[] star = new Star[numStars];

void setup()
{
  // set window & colour options
  size(400,400);
  background (255);
  stroke(140,140,115);
  noFill();
  fill (222,222,197,20);
  noStroke();

  // create stars
  for (int i=0;i<numStars;i++)
  {
    star[i] = new Star();
  }
}


void loop()
{
  // move camera
  translate(200,200,-200);

  // draw stars
  for (int i=0;i<numStars;i++)
  {
    star[i].draw();
  }
}


class Star
{
  float x; float y; float z;       // position
  float ax; float ay; float az;    // rotation
  float ix ; float iy; float iz;   // incerment for rotation
  float s;                         // speed 

  Star(){
    // initialise star with random values
    x= random (600)-300 ; y = random(600)-300 ; z= 500 - random(2500);
    ax = random (TWO_PI) ; ay = random (TWO_PI) ; 
    s = random (8) ;
    ix = random (PI/100)*s ; iy = random (PI/100)*s ; iz = random (PI/100)*s;

  }
  void draw(){
    push();
    
    // update star position, reset if too close
    z=z+s ;      
    if (z>500){
      z=-2000;
    }
    
    // update star rotation, reset if greater then 2xPI
    ax-=ix ; ay+=iy ; 
    if (ax>TWO_PI) {ax=0;}
    if (ay>TWO_PI) {ay=0;}
   
    
    translate(x,y,z);                      // move star to new position 
    rotateX(ax);rotateY(ay);               // rotate object
    box(30);                               // draw object
    pop();
  }
}