The realization space is
  [1   1   0          2*x2 - 1   0   1   1          0          2*x2 - 1         x1 - 1    1]
  [1   0   1   x1*x2 - x1 + x2   0   1   0     x1 - 1   x1*x2 - x1 + x2      x1^2 - x1   x1]
  [0   0   0                 0   1   1   1   2*x2 - 1       2*x2^2 - x2   2*x1*x2 - x1   x2]
in the multivariate polynomial ring in 2 variables over ZZ
avoiding the zero loci of the polynomials
RingElem[x1 - 1, x1*x2 - x1 + x2, x1, x2, x2 - 1, 2*x2 - 1, x1*x2 + x2 - 1, x1 + x2 - 1, x1 - x2, x1 - 2*x2, x1^2*x2 - x1^2 - 4*x1*x2^2 + 4*x1*x2 - x2, x1^2 + 2*x1*x2 - 3*x1 + 1, 2*x1*x2 - 2*x1 + 1, 2*x1^2*x2^2 - 2*x1^2*x2 + x1^2 + 2*x1*x2^2 - 3*x1*x2 + x2, 2*x1*x2^2 - 2*x1*x2 + x1 - x2, x1*x2 - x1 + 2*x2^2 - 2*x2 + 1, x1 + 2*x2 - 2]