x1,x2,x3,x4
-x1,x2,-x3,-x4+1/2
-x1,-x2,-x3,-x4
x1,-x2,x3,x4+1/2
x1+1/2,x2+1/2,x3,x4
-x1+1/2,x2+1/2,-x3,-x4+1/2
-x1+1/2,-x2+1/2,-x3,-x4
x1+1/2,-x2+1/2,x3,x4+1/2