The realization space is
  [1   1   0       x1 - 1   0   1   1                 0       x1 - 1    1                x1]
  [1   0   1   x1*x2 - x1   0   1   0   x1*x2 + x1 - x2   x1*x2 - x1   x1   x1*x2 + x1 - x2]
  [0   0   0            0   1   1   1             x1*x2   x1*x2 - x2   x1             x1*x2]
in the multivariate polynomial ring in 2 variables over ZZ
avoiding the zero loci of the polynomials
RingElem[x1, x1 - x2, x1*x2 - 2*x1 + 1, x1 - 1, 2*x1 - 1, x2, x2 - 1, x1*x2 + x1 - x2, x1^2*x2^2 - x1^2*x2 + 2*x1^2 - 2*x1*x2 - x1 + x2, x1^2*x2^2 - 2*x1^2*x2 + 2*x1^2 - x1*x2 - x1 + x2, x1^2 - 2*x1*x2 - x1 + x2, x1^2 + x1*x2^2 - 2*x1*x2 - x1 + x2, 3*x1^2 - 2*x1*x2 - 2*x1 + x2, 2*x1*x2 - x1 - x2 + 1, 2*x1*x2 + x1 - x2, x1^2*x2^2 + x1^2 - 2*x1*x2 - x1 + x2, x1^2*x2^2 - x1^2*x2 + x1^2 - x1*x2 - x1 + x2]