 
 
     @IBAction func four(sender: UIBarButtonItem) {
-        pouring = false
         vesselViews[3].hidden = false
         vesselViews[4].hidden = true
         let puzzle = puzzles.randomPuzzle(4, difficulty: difficulty)



    @IBAction func hint(sender: UIBarButtonItem) {
        // Solve puzzle and TODO: perform first move. TODO: Also show nr. of remaining pours for solution.
        var caps = [Int]()
        var conts = [Int]()
        for i in 0 ..< activeVessels {

                vessels[destination].contents = CGFloat(destinationFinalContents)
                vesselViews[source].contents = vessels[source].contents
                vesselViews[destination].contents = vessels[destination].contents
                soundManager.sndStop()
                stopPouring()
                // Look if any vessel contains the target contents.
                var winningVessel: Int?
                for i in 0 ..< activeVessels {
