     private func configureMusicStand() {
         // Create the vertical position constraint for the music stand
         let musicStandVerticalConstraint = NSLayoutConstraint(item: musicStand, attribute: .Bottom, relatedBy: .GreaterThanOrEqual, toItem: scrollView, attribute: .Bottom, multiplier: 1, constant: 0)
-        scrollView.addConstraint(musicStandVerticalConstraint)
-        scrollView.addConstraint(NSLayoutConstraint(item: musicStand, attribute: .Top, relatedBy: .GreaterThanOrEqual, toItem: scrollView, attribute: .Top, multiplier: 1, constant: 40))
-        scrollView.addConstraint(NSLayoutConstraint(item: musicStand, attribute: .Width, relatedBy: .LessThanOrEqual, toItem: scrollView, attribute: .Width, multiplier: 1, constant: 0))
-        scrollView.addConstraint(NSLayoutConstraint(item: musicStand, attribute: .Height, relatedBy: .Equal, toItem: musicStand, attribute: .Width, multiplier: 1184.0 / 750.0, constant: 0))
-        scrollView.addConstraint(NSLayoutConstraint(item: musicStand, attribute: .Height, relatedBy: .LessThanOrEqual, toItem: scrollView, attribute: .Height, multiplier: 1, constant: 0))
+        let standTop = NSLayoutConstraint(item: musicStand, attribute: .Top, relatedBy: .GreaterThanOrEqual, toItem: scrollView, attribute: .Top, multiplier: 1, constant: 40)
+        let standWidth = NSLayoutConstraint(item: musicStand, attribute: .Width, relatedBy: .LessThanOrEqual, toItem: scrollView, attribute: .Width, multiplier: 1, constant: 0)
+        let standAspect = NSLayoutConstraint(item: musicStand, attribute: .Height, relatedBy: .Equal, toItem: musicStand, attribute: .Width, multiplier: 1184.0 / 750.0, constant: 0)
+        let standHeight = NSLayoutConstraint(item: musicStand, attribute: .Height, relatedBy: .LessThanOrEqual, toItem: scrollView, attribute: .Height, multiplier: 1, constant: 0)
+        NSLayoutConstraint.activateConstraints([musicStandVerticalConstraint, standTop, standWidth, standAspect, standHeight])
         
         // Keep the right side of the music stand at the right edge of pages 1 and 2
         keepView(musicStand, onPages: [1,2], withAttribute: .Right)

    
    private func configureRazzleDazzleLabels() {
        // Set the size constraints on Razzle and Dazzle
        scrollView.addConstraint(NSLayoutConstraint(item: razzle, attribute: .Width, relatedBy: .Equal, toItem: star, attribute: .Width, multiplier: 0.6, constant: 0))
        scrollView.addConstraint(NSLayoutConstraint(item: razzle, attribute: .Height, relatedBy: .Equal, toItem: razzle, attribute: .Width, multiplier: 218.0 / 576.0, constant: 0))
        scrollView.addConstraint(NSLayoutConstraint(item: dazzle, attribute: .Width, relatedBy: .Equal, toItem: star, attribute: .Width, multiplier: 0.6, constant: 0))
        scrollView.addConstraint(NSLayoutConstraint(item: dazzle, attribute: .Height, relatedBy: .Equal, toItem: dazzle, attribute: .Width, multiplier: 386.0 / 588.0, constant: 0))

        // Create the vertical position constraints for Razzle and Dazzle
        let razzleVerticalConstraint = NSLayoutConstraint(item: razzle, attribute: .CenterY, relatedBy: .Equal, toItem: star, attribute: .CenterY, multiplier: 1, constant: 0)
        let dazzleVerticalConstraint = NSLayoutConstraint(item: dazzle, attribute: .CenterY, relatedBy: .Equal, toItem: star, attribute: .CenterY, multiplier: 1, constant: 0)
        scrollView.addConstraint(razzleVerticalConstraint)
        scrollView.addConstraint(dazzleVerticalConstraint)
        
        // Animate the vertical position of Razzle to go from 30 pixels above the center of the view to 200 pixels above, between pages 0 and 1
        let razzleVerticalAnimation = ConstraintConstantAnimation(superview: scrollView, constraint: razzleVerticalConstraint)

    
    private func configureStar() {
        // Center the star on the page, and keep it centered on pages 0 and 1
        let width = NSLayoutConstraint(item: star, attribute: .Width, relatedBy: .LessThanOrEqual, toItem: scrollView, attribute: .Width, multiplier: 1.3, constant: 0)
        let height = NSLayoutConstraint(item: star, attribute: .Height, relatedBy: .LessThanOrEqual, toItem: scrollView, attribute: .Height, multiplier: 1, constant: 0)
        let top = NSLayoutConstraint(item: star, attribute: .Top, relatedBy: .GreaterThanOrEqual, toItem: scrollView, attribute: .Top, multiplier: 1, constant: 30)
        let aspect = NSLayoutConstraint(item: star, attribute: .Height, relatedBy: .Equal, toItem: star, attribute: .Width, multiplier: 1, constant: 0)
        let centerY = NSLayoutConstraint(item: star, attribute: .CenterY, relatedBy: .Equal, toItem: scrollView, attribute: .CenterY, multiplier: 1, constant: 0)
        NSLayoutConstraint.activateConstraints([width, height, top, aspect, centerY])
        keepView(star, onPages: [0,1])
        
        // Scale up the star to 7 times its original size between pages 0 and 1, with a quadratic Ease In easing function
