         statusLabel.text = "Key(s) Released"
         keysHeld.removeAll(keepCapacity: false)
         midiNotesHeld.removeAll(keepCapacity: false)
+    }
+    
+    func redisplayHeldKeys() {
+        for key in keysHeld {
+            let index = key.tag - 200
+            if blackKeys.contains(index) {
+                key.setImage(UIImage(named: "blackkey"), forState: .Normal)
+            } else {
+                key.setImage(UIImage(named: "whitekey"), forState: .Normal)
+            }
+        }
     }
     
     func toggleKeyHeld(key: UIButton) {

        statusLabel.text = "Keyboard Octave Up"
        keyboardOctavePosition += 1
        octavePositionLabel.text = String(keyboardOctavePosition)
    }
    
    @IBAction func holdModeToggled(sender: UIButton) {

        keyboardOctavePosition += -1
        octavePositionLabel.text = String(keyboardOctavePosition)
        // update Keyboard keys held/etc
        redisplayHeldKeys()
        
    }
    
    @IBAction func octaveUpPressed(sender: UIButton) {
