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