Daesh deploys decoys. They may not look at all realistic from the ground, but they're hoping that they can trick airstrikes into bombing the fabrications rather than them. They even mount mannequins on the wooden tanks in an effort to convince air support that these are the real deal.
It hasn't worked, and analysts consider the ploy a sign that Daesh are losing resources and thus growing desperate. They must be running low on idiots willing to throw themselves into the meat-grinder. Certainly, their "leaders" don't want to volunteer; they're into Barry's approach: lead from behind.