Don't the titles "Gimme Some Lovin'" and "Let's Get It On" make you want to get it on and indulge in a spot of lovin' much more than "I Want Your Sex"?

And if Bruce Springsteen had been told "Just play some songs, 'kay?" instead of "You’ve got 720 seconds, then we cut to commercials", would his Super Bowl half-time show have been half as electric?

Silly restrictions - and the sillier and more arbitrary they are, the better - inspire people to raise their game, whereas free-for-alls and anything-goeses don’t open the doors of perception; more often than not, they just let the mediocrity come flooding in.

Isn't Rory Gallagher here - staying firmly inside the suffocatingly small box of the breakneck 12-bar blues format - a lot more interesting to listen to than, say, Steve Howe freeforming at the mouth? (Wind on to 0:55, where the fun starts.)

There must be lots more examples of brilliance shining through despite being bound within seemingly absurd limits that have been placed on the words, the music or the running time.