The most beautiful and unusual tuning I came across is alternating major and minor thirds, something like ACEGBD. Then you can tune A,E,B down 15 cents and each

The most beautiful and unusual tuning I came across is alternating major and minor thirds, something like ACEGBD. Then you can tune A,E,B down 15 cents and each group of three consecutive strings (open or mini-barred at any fret) becomes a _just intonation_ major or minor chord. You pluck three strings and it's like plucking one static string, a sound hanging in space without movement. Major and minor just intonation scales are also playable, though require some jumps.