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