Blacksmiths making farm implements at Ambatovaky, a village of blacksmiths not too distant from the Ranomafana National Park. Their bellows are made from two hollowed-out tree trunks through which a person forces air, like a piston, using cloth wads attached to the ends of two poles. While air in one 'cylinder' is being pushed down, the pole in the other is being quickly raised so as to give a continuous air supply to the charcoal fire. The process is physically exerting, which is why young men operate the forges.