  We find a closed-form expression for the Poisson's coefficient of
curved-crease variants of the ``Miura ori'' origami tessellation. This is done
by explicitly constructing a continuous one-parameter family of isometric
piecewise-smooth surfaces that describes the action of folding out of a
reference state. The response of the tessellations in bending is investigated
as well: \comment{using a numerical convergence scheme,} the effective normal
curvatures under infinitesimal bending are found to occur in a ratio equal and
opposite to the Poisson's coefficient. These results are the first of their
kind and, by their simplicity, should provide a fruitful benchmark for the
design and modeling of curved-crease origami and compliant shell mechanisms.
Here, the developed methods are used to design a curved crease 3D morphing
solid with a tunable self-locked state.
