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