The realization space is
  [1   1   0   -2*x1^2 + 2*x1 - 1   0   1   1                            0   -2*x1^2 + 2*x1 - 1         1    1]
  [0   1   1            x1^2 - x1   0   0   1   2*x1^3 - 5*x1^2 + 4*x1 - 1            x1^2 - x1   -x1 + 1   x1]
  [0   0   0                    0   1   1   1        -2*x1^3 + 2*x1^2 - x1                -x1^2        x1   x1]
in the multivariate polynomial ring in 1 variable over ZZ
avoiding the zero loci of the polynomials
RingElem[x1, 2*x1 - 1, x1 - 1, 2*x1^2 - 2*x1 + 1, 4*x1^4 - 9*x1^3 + 10*x1^2 - 5*x1 + 1, 4*x1^3 - 7*x1^2 + 5*x1 - 1, 4*x1^2 - 5*x1 + 2, 3*x1^2 - 3*x1 + 1, 5*x1^3 - 8*x1^2 + 5*x1 - 1, 4*x1^4 - 7*x1^3 + 7*x1^2 - 4*x1 + 1, 8*x1^5 - 21*x1^4 + 27*x1^3 - 19*x1^2 + 7*x1 - 1]