{af-be,ag-ce,ah-de,bg-cf,bh-df,ch-dg, aj-bi,ak-ci,al-di,bk-cj,bl-dj,cl-dk, an-bm,ao-cm,ap-dm,bo-cn,bp-dn,cp-do, ej-fi,ek-gi,el-hi,fk-gj,fl-hj,gl-hk, en-fm,eo-gm,ep-hm,fo-gn,fp-hn,gp-ho, in-jm,io-km,ip-lm,jo-kn,jp-ln,kp-lo} { (1,2,3,0,5,6,7,4,9,10,11,8,13,14,15,12), (1,0,2,3,5,4,6,7,9,8,10,11,13,12,14,15), (4,5,6,7,8,9,10,11,12,13,14,15,0,1,2,3), (4,5,6,7,0,1,2,3,8,9,10,11,12,13,14,15), (0,4,8,12,1,5,9,13,2,6,10,14,3,7,11,15) } a b c d e f g h i j k l m n o p