...
It allows users to ear train. After hitting start, machine starts playing notes according to difficulty level, and the user guesses the notes by playing them on keyboard. User can also share expertise (which difficulty level he is doing) to his friends. (Hitting “share expertise” button will give him a link, which states his expertise, to email to other people. 
Design 2:
It allows users to “free-play” keyboard as well as record what they play. The user can extract the recorded music and get it as a text of notes, to refer at a later time or email to friends. 
Design 3:
It’s a gamified version which maintains a scoreboard of people who play in the same computer. 
Keshav:
All designs have a create account page. A home page which is a sort of list of items. And lesson pages. The designs differ on, among other things, how everything is structured.
...