K=PD[X[1,21,2,20], X[19,3,20,2], X[3,9,4,8], X[9,5,10,4], X[5,11,6,10],
X[16,11,17,12], X[12,17,13,18], X[18,13,19,14], X[21,15,22,14],
X[15,23,16,22],
X[24,7,1,8], X[6,23,7,24]]