or this https://www.youtube.com/watch?v=PnzQP4M_BQk (Pi) or this https://www.youtube.com/watch?v=a_uL29CKzW8&list=PLpn7yEHjyr... and others (Impressions On Chopin). Not some theory, you can hear the strings bending. Enjoy!
@4d4m: Yes. - and more.. to have such freedom of expression (and some fun, https://www.youtube.com/watch?v=fRj9I5qiiI4 ).