They should meander like a stream. This helps deepen the landscape by adding layers. The path can be the river, or a path along it, or the tracing of the sun through the sky over the shoulder of the mountain. The concept is to never create inorganic patterns, but instead to mimic the patterns that nature creates. "The Threshold" – The path should lead to a threshold. The threshold is there to embrace you and provide a special welcome. The threshold can be the mountain, or its shadow upon the ground, or its cut into the sky. The concept is always that a mountain or its boundary must be defined clearly. "The Heart" – The heart is the focal point of the painting and all elements should lead to it. The heart defines the meaning of the painting. The concept should imply that each painting has a single focal point, and that all the natural lines of the painting direct inwards to this point. "Shan shui" is painted and designed in accordance with Chinese elemental theory with five elements representing various parts of the natural world, and thus has specific directions for colorations that should be used in 'directions' of the painting, as to which should dominate. Positive interactions between the Elements are:   Elements that react positively should be used together. For example, Water complements both Metal and Wood; therefore, a painter would combine blue and green or blue and white. There is a positive interaction between Earth and Fire, so a painter would mix Yellow and Red. Negative interactions between the Elements are:   Elements that interact negatively should never be used together. For example, Fire will not interact positively with Water or Metal so a painter would not choose to mix red and blue, or red and white. A certain movement in poetry, influenced by the "shan shui" style, came to be known as "Shanshui poetry". Sometimes, the poems were designed to be viewed with a particular work of art, others were intended to be "textual art" that invoked an image inside a reader's mind. The art form of "shan shui" has been popular to the point where a Chinese animation from 1988 entitled "Feeling from Mountain and Water" uses the same art style and even the term for the film's title. Additionally, many recent movies and plays produced in China, specifically "House of Flying Daggers" and "Hero", use elements of the style itself in the sets, as well as the elemental aspects in providing "balance". The term "shan shui" is sometimes extended to include gardening and landscape design, particularly within the context of "feng shui".