There's one guy on youtube who claims Bach's squiggles underneath each piece title in the original WTC manuscript actually represents an ideal tuning system for

There's one guy on youtube who claims Bach's squiggles underneath each piece title in the original WTC manuscript actually represents an ideal tuning system for that piece. I thought that was a crackpot theory, but then he played some pieces in their respective individual tuning systems on a harpsichord, and they sounded absolutely amazing, better than well tempered (or equal obviously). So who knows!