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