Changes we made since GR4 as per users feedback:- 

• Exercises
  • * Better structure for exercises. 
  • * Exercises more dynamic (previously had only one hard coded exercise) 
• Appearance
  • * Visualization of active keys. 
  • * Color scheme (wood background! yay!) and more aesthetic look. 
• Simplifications
  • * Removed musical notes from everywhere (not required for ear training) 
• Misc UX 
  • * Implemented settings. They persist over multiple sessions using cookies.
  • * Center keys on keyboard are used to play piano => more ergonomic
  • * Feedback messages more helpful. Indicates when to use piano vs buttons
• Piano sound 
  • * Better quality of musical sound (using MIDI library). 
  • * Can play multiple musical notes at the same time. 
• * Efficiency
  • Sped up animation of panels 
  • You don't have to wait one second for "Listen dialog" to show up and go away  
  • * Keyboard shortcuts for buttons while ear training