  Wrinkling is an $h$-principle technique, introduced by Eliashberg and
Mishachev, that can be used to prove statements of the form: "formal solutions
of a partial differential relation $\mathcal{R}$ can be deformed to
singular/wrinkled solutions". What a wrinkled solution is depends on the
context, but the overall idea is that it should be an object that fails to be a
solution due to the presence of mild/controlled singularities.
  Much earlier, Haefliger structures were introduced by Haefliger as singular
analogues of foliations. Much like a foliation is locally modelled on a
submersion, a Haefliger structure is modelled on an arbitrary map. This implies
that Haefliger structures have better formal properties than foliations. For
instance, they can be pulled back by arbitrary maps and admit a classifying
space.
  In [8], the second and third authors generalised the wrinkled embeddings of
Eliashberg and Mishachev to arbitrary order. This paper can be regarded as a
sequel in which we deal instead with generalisations of wrinkled submersions.
The main messages are that: 1) Haefliger structures provide a nice conceptual
framework in which general wrinkling statements can be made. 2) Wrinkling can
be interpreted as holonomic approximation into the \'etale space of solutions
of the relation $\mathcal{R}$.
  These statements imply connectivity statements relating (1) $\mathcal{R}$ to
its \'etale space of solutions and (2) the classifying space for foliations
with transverse $\mathcal{R}$-geometry to its formal counterpart.
