Isomeric FLID in 31-tET

Well, I found a FLID in 31-tET (31/15's only perfect FLID) that
is Z-related. In fact, it is a quadruple.

The Affine group of 31-tET is much more complicated than in 22-tET
I am crunching Aff(31) in GAP these days.

Anyway these FLIDs relate to Difference Sets, and Projective Planes
and Steiner Systems and so forth. What's the relevance to tuning?

I think the answer lies in understanding properties of scales,
Rothenberg and so forth.

ZCount Field2 Field3

4 [777777777777777]__31__15
(0,1,2,4,6,10,11,12,13,15,16,18,19,23,26)__31__15
4 [777777777777777]__31__15
(0,1,2,5,9,11,13,14,15,16,18,19,21,24,25)__31__15
4 [777777777777777]__31__15
(0,1,3,4,7,8,9,10,12,15,17,19,20,21,25)__31__15
4 [777777777777777]__31__15
(0,2,3,4,6,7,9,11,14,15,16,17,21,22,25)__31__15

PGH