  We give a geometric characterisation of those groups that arise as fixed
subgroups of finite-order untwisted automorphisms of right-angled Artin groups
(RAAGs). They are precisely the fundamental groups of a class of compact
special cube complexes that we term "divisible".
  The main corollary is that surface groups arise as fixed subgroups of
finite-order automorphisms of RAAGs, as do all commutator subgroups of
right-angled Coxeter groups. These appear to be the first examples of such
fixed subgroups that are not themselves isomorphic to RAAGs.
  Using a variation of canonical completions, we also observe that every
special group arises as the fixed subgroup of an automorphism of a finite-index
subgroup of a RAAG.
