Paper Piano

So I recently watched this video I made and put on youtube when I was 16 and apparently a lot of people have a lot of things to say about it. Like how ugly my nails are - and looking back, orange is not a very attractive nail color on me I will admit that!
Anyways, it is fun to see people theorizing how I did this. such as this comment:
"if you set up an AR program to obsreve the paper with a web cam, recognise the design of a keyboard and produce a tone when contact is made with a particular point... I have never seen auditory AR but it should be no more complex than the visual programs already existing, the only hard part would be making it recognise the hand drawn keyboard, and making it accurate in seeing which hey is being hit..."
uh wahhhh?

Oh the internet.