replaced 	tunique().reverse().mirror() by 	tunique().mirror()
replaced
	tunique().reverse().mirror()
by
	tunique().mirror()

tunique() returns the unique tails in the head and a void tail;
mirror()  duplicates the head;
hence, the reverse() is not needed (actually even wrong), here.

zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb