Pattern Password CM13 bigger than 3x3

[MyerSmith]

I want to use a patter and a strong (boot) password.

My question is how it generate a string password from the patter, so I can use it in SnooperStopper.
3x3 seems easy:
0 1 2
3 4 5
6 7 8
http://resources.infosecinstitute.com/android-forensics-cracking-the-pattern-lock-protection/

But bigger pattern seems to have a other scheme.

omnirom/android_bootable_recovery@7a48a66

How I can generate them ?

[snevas]

3x3 isn't usable in LineageOS 14.1 as well in string form (just tested this). They have a different approach to patterns as 'normal' android.