0..13 1..13 x[] d[] eq(%0,dist(%1,%2)) d[0] x[1] x[0] d[1] x[2] x[1] d[2] x[3] x[2] d[3] x[4] x[3] d[4] x[5] x[4] d[5] x[6] x[5] d[6] x[7] x[6] d[7] x[8] x[7] d[8] x[9] x[8] d[9] x[10] x[9] d[10] x[11] x[10] d[11] x[12] x[11] d[12] x[13] x[12]