BTW, the parentheses appear to be a tricky way to combine the backward and all other directions in a continuation step of a single atom. (Nice find, but perhaps a bit non-obvious.) It might be inefficient to not have a 1 behind it, though, as now it is expanded as maKmabKmabbKmabbbK...
I suppose the 2-step cannot pass a turn.
BTW, the parentheses appear to be a tricky way to combine the backward and all other directions in a continuation step of a single atom. (Nice find, but perhaps a bit non-obvious.) It might be inefficient to not have a 1 behind it, though, as now it is expanded as maKmabKmabbKmabbbK...