int xdist = 10;

void setup( ) {
  size(900, 200);
  background(255);
  noStroke( );
  noLoop( );
}

void draw( ) {
  scale(0.50);
  box(6);
}

void box(int level) { 
  if (level > 0) {
    level = level - 1;
    fill(paint(level));
    rect(xdist, 20+level*30, 20, 20);
    xdist = xdist + 25;
    box(level);
    box(level);
  } else {
    return;  }
}

color paint(int level) {
    return color(170,170,170);
}