So instead of:

my @previous = qw(EF ABE ABCD)

I'd have:

my @previous = (
	[qw(ABE ABCD)],	#A slot
	[qw(ABE ABCD)],	#B slot
	[qw(ABC)],		#C slot
	[qw(ABCD)],		#D slot
	[qw(EF ABE)],	#E slot
	[qw(EF)]		#F slot
);