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