     
     @IBAction func buttonPress(_ sender: UIButton) {
         //2. Play the current subphrase with the tone of the pressed button.
+        
+        //if the audio is already playing, don't do anything:
+//        guard audioPlayer.isPlaying == false else {
+//            return
+//        }
         
         var sendingButton: UIButton?
         

            if newScore < 0 {
                newScore = 0
            }
            setCurrentScore(newScore: newScore)
            refreshScore()
        }
    }
    

        
        //audio
        audioEngine = AVAudioEngine()
        audioPlayer = AVAudioPlayer()
        //setup node
        audioPlayerNode = AVAudioPlayerNode()
        audioEngine.attach(audioPlayerNode)
