21 note CS lattice

Here's a lattice for Paul's 21 note constant structure.

9^------5
/ \ /
1 / 4 \ 7 / 0v------6v
/ \ /
0---3---6---9---2v--5v--8v
\ / \ /
2 \ 8 / 1v\ 4v/ 7v
\ / \ /
3v------9v

3, 9 and 5v are the only intervals of 11. Everything else is at the
simplest 7-prime limit location. Here's the decimal translation:

6 1/1
7v 21/20 7 15/14
8v 9/8 8 8/7
9v 6/5 9 11/9 9^ 5/4
0v 21/16 0 4/3
1v 7/5 1 10/7
2v 3/2 2 32/21
3v 8/5 3 18/11
4v 12/7 4 7/4
5v 11/6 5 15/8
6v 63/32 6 2/1

Graham