Why use aa when you could use ab? In Betza notation directional modifiers indicating direction sets with an empty intersection means one or the other, and a and b do not have moves in common.
D'oh! I didn't think of that. ab it is.
Edit: That doesn't quite work as advertised on the ID, actually.
D'oh! I didn't think of that. ab it is.
Edit: That doesn't quite work as advertised on the ID, actually.