3-5-7-15 by 9/8 bihexany

A 7-limit bihexany. This creates a scale of 1 9/8 7/6 5/4 21/16 7/5 45/32 3/2 63/40 27/16 7/4 63/32 2/1, with steps of 9/8 28/27 15/14 21/20 16/15 225/224 16/15 21/20 15/14 28/27 9/8 64/63. Since the base hexany contains every interval in the 7-odd-limit tonality diamond, this may seem like the obvious choice for expanding it outwards, and it does indeed contain at least one copy of every interval in the 9-odd-limit tonality diamond, including 6 perfect fifths. However, it also contains two steps that are small enough to blur into their neighbours, making it closer to a decatonic scale for melodic purposes and no longer optimal for its size.

! 3-5-7-15_by_9/8_Hexany.scl
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3 5 7 15 by 9/8 2-combination Hexany
12
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203.910
266.871
386.313
470.781
582.512
590.223
701.955
786.422
905.865
968.825
1172.735
1200