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