x_1, x_10, x_11, x_12, x_2, x_3, x_4, x_5, x_6, x_7, x_8, x_9, 
-x_10*x_3+x_10*x_8-x_2*x_8
-x_1*x_11+x_11*x_6-x_6*x_9
-x_12*x_3+x_12*x_6-x_2*x_6
-x_1*x_10+x_10*x_7-x_7*x_9
-x_12*x_5+x_12*x_7-x_4*x_7
-x_11*x_5+x_11*x_8-x_4*x_8
