The realization space is
  [1   0   1   x1*x2 - x2 + 1   x1^2*x2 - 3*x1*x2 + x1 + 2*x2 - 1    1                 0      x1*x2 - 2*x2 + 1   0    1    1]
  [0   1   1       x1*x2 - x2                         -x1*x2 + x2   x1                 1                   -x2   0    0   x1]
  [0   0   0   x1*x2 - x2 + 1                     -x1*x2 + x2 - 1    1   -x1*x2 + x2 - 1   x1*x2^2 - x2^2 + x2   1   x2   x2]
in the multivariate polynomial ring in 2 variables over ZZ
avoiding the zero loci of the polynomials
RingElem[x2, x1, x2 - 1, x1^2*x2^2 - 3*x1*x2^2 + 2*x1*x2 + 2*x2^2 - 2*x2 + 1, x1*x2 - x2 + 1, x1 - 1, x1^2*x2 - 2*x1*x2 + x1 + x2, x1^2*x2 - x1*x2 + x1 + x2, x1*x2^2 - x1*x2 + 2*x2 - 1, x1^2*x2 - 2*x1*x2 + x1 + 2*x2 - 1, x1^4*x2^2 - 4*x1^3*x2^2 + 2*x1^3*x2 + 7*x1^2*x2^2 - 5*x1^2*x2 + x1^2 - 7*x1*x2^2 + 6*x1*x2 - x1 + 3*x2^2 - 3*x2 + 1, x1^2*x2 - x1*x2^2 - x1*x2 + x1 + x2^2, x1*x2 - 2*x2 + 1, 2*x1^2*x2^2 - 5*x1*x2^2 + 3*x1*x2 + 3*x2^2 - 3*x2 + 1, x1^2*x2 - x1*x2 + x1 - x2 + 1, x1^2*x2 - x1*x2 + x1 + 1, x1*x2^2 - x1*x2 - x2^2 + 3*x2 - 1]