Of course it's not useful, Don, it was born of idle curiosity and the age old scientific method of testing a hypothesis. *sigh* Lighten up I'm relaxing on holiday and it passed a pleasant five minutes running through a few songs for little reason apart from interest.

The Pachabel rant by Rob Paravonian which I'm sure you'll have seen is much in the same vein pointing out similarities in a lighthearted way.

When I started to play and learn some session tunes when I took up the mandolin I came across all sorts of tunes where time so alters things.