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