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