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