P[2(0,P[2(0,-2)(2,1)])(2,P[0(0,1)])]
P[2(0,P[2(0,2)(1,-4)(2,4)])(1,P[0(0,-4)])(2,P[0(0,1)])]
P[2(0,P[1(1,1)])(2,P[0(0,-1)])]
