The realization space is
  [1   1   0   1   0   0              1                                           x1 - x2                     1    1    1]
  [1   0   1   1   0   1   -x1 + x2 + 1   -x1^2*x3 + 2*x1*x2*x3 + x1*x3 - x2^2*x3 - x2*x3   -x1*x3 + x2*x3 + x3   x2   x2]
  [0   0   0   1   1   1              1                            x1*x3 - x2*x3 - x3 + 1                    x3   x1   x3]
in the multivariate polynomial ring in 3 variables over ZZ
within the vanishing set of the ideal
Ideal (x1^3*x3 - 2*x1^2*x2*x3 - x1^2*x3 + x1*x2^2*x3 + 2*x1*x2*x3 - x2^2*x3 - x2*x3 + x2)
avoiding the zero loci of the polynomials
RingElem[x2 - 1, x1 - x3, x2, x1 - 1, x1*x3 - x2*x3 + x2 - x3, x3, x3 - 1, x1*x3 - x2*x3 - x3 + 1, x1*x3 - x2*x3 + x2 - 1, x1^2*x3^2 - 2*x1*x2*x3^2 + x1*x2*x3 - x1*x3^2 + x2^2*x3^2 - x2^2*x3 + x2*x3^2 - x2*x3 + x2, x1^2*x3 - 2*x1*x2*x3 + x1*x2 - x1*x3 + x2^2*x3 - x2^2 + x2*x3 - x2 + 1, x1^2*x3 - 2*x1*x2*x3 + x1*x2 - x1*x3 + x2^2*x3 - x2^2 + x2*x3 - x3 + 1, x1 - x2 - 1, x1 - x2, x2 - x3 - 1, x2 - x3, x1^2*x3 - x1*x2*x3 - x1*x3 + x1 + x2*x3 - x3, x1*x3 - 2*x3 + 1, x1 - x2 + 1, x1^2 - x1*x2 - x1*x3 + x2*x3 + x3 - 1, x1^3*x3 - 2*x1^2*x2*x3 - 2*x1^2*x3 + x1^2 + x1*x2^2*x3 + 4*x1*x2*x3 - 2*x1*x2 - 2*x2^2*x3 + x2^2 - x2*x3 + x2 + x3 - 1, x1, x1*x3 - x2*x3 + 1, x1^2*x3 - 2*x1*x2*x3 + x2^2*x3 - x3 + 1]