  Recent static experiments on twist effects in chiral three-dimensional
mechanical metamaterials have been discussed in the context of micropolar
Eringen continuum mechanics, which is a generalization of Cauchy elasticity.
For cubic symmetry, Eringen elasticity comprises nine additional parameters
with respect to Cauchy elasticity, of which three directly influence chiral
effects. Here, we discuss the behavior of the static case of an alternative
generalization of Cauchy elasticity, the Milton-Briane-Willis equations. We
show that in the homogeneous static cubic case only one additional parameter
with respect to Cauchy elasticity results, which directly influences chiral
effects. We show that the Milton-Briane-Willis equations qualitatively describe
the experimentally observed chiral twist effects, too. We connect the behavior
to a characteristic length scale.
