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