I witnessed an amazing piece of flying by a balloonatic in Swansea. It was at a car show near the coast. The field sloped up from the road and had trees across the top and down one side. This incredible chap lifted off from the bottom of the hill and was blown gently up the slope. He then descended to near ground level at the top and due to some air currents around the trees which he obviously was aware of he descended the hill sheltered by the trees. He was actually flying a rectangular circuit and returning to the takeoff point. And he did it for most of the afternoon!! Amazing to watch.