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