23. Tuplo

This guitar features a fixed tuning of B-E-B-E-B-E (all half-flat).

The fretting contains an 18-tone JI scale of all the 23-Prime-Limit harmonics between 24 and 48.

The scale in that octave is 24-25-26-27-28-30-32-33-34-35-36-38-39-40-42-44-45-46-48.

Or ... 1/1-33/32-17/16-35/32-9/8-19/16-39/32-5/4-21/16-11/8-45/32-23/16-3/2-25/16-13/8-27/16-7/4-15/8.
The split frets are the same for each pair.  See below for tuning/fretting charts.