I can't figure how to get the string which is suppose to be line for the balloon. Here how it looks like;
http://imgur.com/jjhZJ

float bX = 50;
float bY = 60;
float bWidth = 70;
float bHeight = 80;
color balloonColor = color(0, 0, 255);
float bHSpeed = 2;
float bVSpeed = 2;

void setup()
{
  size(300, 300);
  bWidth = random(10, 70);

  bHeight = random(10, 80);

  balloonColor = color(random(0, 255), random(0, 255), random(0, 255)); // randomly set the balloon color

  ellipse(bX + 50, bY + 60, bWidth + 70, bHeight + 80); // set bX and bY; make sure that the balloon
  //will be entirely on screen when it starts

  bX = random(bWidth / 2.0, width - bWidth / 2.0);
  bHSpeed = 2;
  bVSpeed = 2;
  smooth();
}

void draw( )
{
  bX += bHSpeed;
  bY += bVSpeed;


  background(255);
  drawHouse(20, 155, 95, 95);
  drawHouse(150, 80, 120, 170);


  drawBalloon(bX, bY, bWidth, bHeight, balloonColor);// draw the balloon by calling drawBalloon()

  bX += bHSpeed;

  if (bX < bWidth / 2 || bX > width - bWidth / 2)
  {
    bHSpeed = -bHSpeed;
  }
  if (bY < bHeight / 2 || bY > width - bHeight / 2)
  {
    bVSpeed = -bVSpeed;
  }
}

void drawBalloon(float x, float y, float w, float h, color c)
{
 
  fill(c, 50);
  ellipse(x, y, w, h);
  fill(10, 30, 110, 20);
}

void drawHouse(float x, float y, float w, float h)
{
  float topY = y + h / 3.0;
  fill(255);
  stroke(0);
  triangle(x + w / 2.0, y, x, topY, x + w, topY);
  rect(x, topY, w, 2.0 * h / 3.0);
  rect(x + w / 8.0, y + h / 3.0 + (0.125) * 2 * h / 3.0, w / 8.0, h / 8.0);
  rect(x + 5.0 / 8.0 * w, y + 3.0 / 4.0 * h, 3.0 / 16.0 * w, h / 4.0);
}