The realization space is
  [1   0   1        1   0   1    x1 - 1    0    1    1]
  [0   1   1   x1 + 1   0   0         0    1    1   x1]
  [0   0   0        0   1   1   -x1 - 1   -1   -1    1]
in the multivariate polynomial ring in 1 variable over ZZ
within the vanishing set of the ideal
Ideal (2*x1^3 + 6*x1^2 + 4*x1)
avoiding the zero loci of the polynomials
RingElem[x1 + 1, 2, x1 - 1, x1, 2*x1 + 1]