 		let now = NSDate().timeIntervalSinceReferenceDate
 		let cycle = now / WigglePhaseDuration
 		let sign = (indexInCollection % 2 == 0) ? +1.0 : -1.0
-		let phase = sin(cycle * M_PI + _cycleOffset * M_PI ) * sign
+		let phase = sin(cycle * M_PI + cycleOffset * M_PI ) * sign
 		let angle = CGFloat(phase * WiggleAngleMax)
 		let layer = self.layer
 		UIView.performWithoutAnimation { () -> Void in

	override func traitCollectionDidChange(previousTraitCollection: UITraitCollection?) {
		let flowLayout = self.collectionView.collectionViewLayout as! UICollectionViewFlowLayout
		let bigItemSize = CGSize(width: 256, height: 360)

		if traitCollection.horizontalSizeClass == .Compact || traitCollection.verticalSizeClass == .Compact {
			let minDimension = min(view.bounds.width,view.bounds.height);
			let width = round(minDimension / 3)
			flowLayout.itemSize = CGSize(width: width, height: round(width * bigItemSize.height/bigItemSize.width))
		} else {
			flowLayout.itemSize = bigItemSize
		}

			})
	}

	private let cycleOffset:NSTimeInterval = drand48() / 2
	private var phase:NSTimeInterval = 0
	private var wiggleAnimationDisplayLink:CADisplayLink?

	func startWiggling() {
		wiggleAnimationDisplayLink = CADisplayLink(target: self, selector: "updateWiggleAnimation")
		wiggleAnimationDisplayLink!.addToRunLoop(NSRunLoop.mainRunLoop(), forMode: NSRunLoopCommonModes)
	}

	dynamic func updateWiggleAnimation() {
