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