A.p↑.rlinkllink:=q;p↑.rlink:=q;q↑.llink:=p;q1.rlink:=p↑.rlink;
B.p↑.llinkrlink:=q;p↑.llink:=q;q↑.rlink:=p;q1.llink:=p↑.1link;
C.q↑.llink:=p;q↑.rlink:=p↑.rlink;p↑.rlinkllink:=q;p↑.rlink:=q;
D.q↑.rlink:=p;q↑.llink:=p↑.1link;p↑.1linkrlink:=q;p↑.llink:=q;