Prokofiev's Sixth Sonata and Black Sabbath

We went to a Murray Perahia concert last night. He had stopped performing for a while in the early nineties due to a hand problem. It turns out he has stopped again, and instead we heard Anne-Marie McDermott, who's not one of the great pianists of the world but oh well. She played some Bach competently if not that engagingly, and then Prokofiev's Piano Sonata No. 6 quite well.

From the program notes by Keith Horner:

The biting harmonies of the sonata's opening movement are built around the clash between A major and A minor. The tonalites first collide in the opening measures of the piece, over a disorienting left-hand tritone. (A tritone is the mosst unsettling and tonally distant of musical intervals. Known as the devil's interval--diabolus in musica--it has provided fuel and color for composers for centuries, including Lizst, Black Sabbath in its self-titled signature song, Bloodrock in "DOA", and for many other heavy metal bands. Tritones appear throughout the Sixth Sonata from the first page to the last.)