Japanese gardens are a living work of art in which the plants and trees are ever changing with the seasons. As they grow and mature, they are constantly sculpted to maintain and enhance the overall experience; hence, a Japanese garden is never the same and never really finished. The underlying structure of a Japanese garden is determined by the architecture; that is, the framework of enduring elements such as buildings, verandas and terraces, paths, tsukiyama (artificial hills), and stone compositions. Over time, it is only as good as the careful maintenance that it receives by those skilled in the art of training and pruning. Part of the art is to keep the garden almost still, like a painting.