override func didMoveToView(view: SKView) {


    /// GRID ///

    grid.anchorPoint = CGPointMake(0.5, 0.5)
    grid.position = CGPointMake(self.size.width / 2, self.size.height / 2)
    grid.size.width = self.size.width * 0.8
    grid.size.height = grid.size.width
    grid.zPosition = 10
    self.addChild(grid)


    /// BALL ///

    ball.anchorPoint = CGPointMake(0.5, 0.5)
    ball.size.width = grid.size.width / 5
    ball.size.height = ball.size.width
    ball.position = CGPointMake(0, 0) // THE BALL IS AT THE CENTER OF THE GRID
    grid.addChild(ball)


    // SWIPE DOWN DETECTION

    let swipeDown:UISwipeGestureRecognizer = UISwipeGestureRecognizer(target: self, action: Selector("swipeDown:"))
    swipeDown.direction = .Down
    view.addGestureRecognizer(swipeDown)


}


func swipeDown(send:UISwipeGestureRecognizerDirection) {


    let moveAction = SKAction.moveBy(CGVectorMake(0, -grid.size.height / 5), duration: 0.1)
    ball.runAction(moveAction)


}