  We show that there is a distortion element in a finitely-generated subgroup
$G$ of the automorphism group of the full shift, namely an element of infinite
order whose word norm grows polylogarithmically. As a corollary, we obtain a
lower bound on the entropy dimension of any subshift containing a copy of $G$,
and that a sofic shift's automorphism group contains a distortion element if
and only if the sofic shift is uncountable. We obtain also that groups of
Turing machines and the higher-dimensional Brin-Thompson groups $mV$ admit
distortion elements; in particular, $2V$ (unlike $V$) does not admit a proper
action on a CAT$(0)$ cube complex. The distortion element is essentially the
SMART machine.
