The frets are spaced on the fretboard so as to divide the strings into small whole number ratios. The six strings can each be tuned to vibrate at any frequency. Using precise whole number ratios improves the clarity of the sound of the intervals, which are out of tune in a typical guitar.  This guitar is tuned to various frequencies, in particular, 432Hz and 444Hz for their mathematical and aesthetic qualities.   

Fretboard Ratios

16:15  9:8  7:6  6:5  5:4  4:3  7:5  3:2  8:5  5:3  7:4  9:5  15:8  2:1