! dudon_evan_thai.scl
Evan differentially-coherent double Thai heptaphone
 12
!
 14107/14080
 243/220
 6235/5632
 537/440
 74/55
 2373/1760
 327/220
 5243/3520
 289/176
 23171/14080
 3193/1760
 2/1
! Evan recurrent sequence   2x^5 = 16 - x  
! (592 -537 = 55 etc.)     x = 1.4864447215647
! the black keys follow a second spiral cycle  x^7 / 16,  or  3.67 c. higher
! Dudon 2009