Proposed Sagittal notation for porcupine

7-limit porcupine temperament
[<1, 2, 3, 2], <0, -3, -5, 6]>

/|) [2, 2, -1, -1> (+1, -7)
||\ [-7, 3, 1> (+2, -14)
/||\ [-11, 7> (+3, -21)

G/||\ A||\
B/|) C/||\ D||\
E/|) F/||\ G||\
A/|) B C||\
D/|) E F||\
G/|) A B\!)
C/|) D E\!)
F/|) G A\!)
B!!/ C D\!)
E!!/ F G\!)
A!!/ B\!!/ C\!)
D!!/ E\!!/ F\!)
G!!/ A\!!/

Tentatively, /|) seems to be a better notation than /| for the (+1, -7) accidental, since /| ordinarily represents a much smaller interval, and the melodic sequence D E\! F/| G appears to be part of an ordinary diatonic scale. The idea is that steps of the scale should appear to be a bit smaller than whole steps.

One problem is that G/||\ is a lot higher than A\||/ -- just a small step below A, actually. An alternative is to use ~|) for (-2, +15), and notate G/||\ as A!~) .

~|) [-4, -1, 0, 2> (-2, +15)
/|) [2, 2, -1, -1> (+1, -7)
||\ [-7, 3, 1> (+2, -14)

21 A~!) 26 A||\
31 B/|) 36 D~!) 04 D||\
09 E/|) 14 G~!) 19 G||\
24 A/|) 29 B 34 C||\
02 D/|) 07 E 12 F||\
17 G/|) 22 A 27 B\!)
32 C/|) 00 D 05 E\!)
10 F/|) 15 G 20 A\!)
25 B!!/ 30 C 35 D\!)
03 E!!/ 08 F 13 G\!)
18 A!!/ 23 A~|) 28 C\!)
33 D!!/ 01 D~|) 06 F\!)
11 G!!/ 16 G~|)

This still has sharps and flats crossing each other -- e.g., D||\ is higher than E!!/ , but not by much. This can be fixed at the cost of additional accidentals -- E'!!) in place of D||\ , A'!!) in place of G||\ . But the crossing of sharps and flats is typical enough with tunings having narrow fourths / wide fifths. Here's a case where the simplicity of remembering the notation might outweigh problems with notating sequences of notes in one direction.

While this notation suffices for porcupine[37], if there's any chance someone might want to use porcupine[59], the first notation is more easily extended.