Many abstract visual metaphors based on organic structures and patterns are found in literature on the Internet's infrastructure. Often, these metaphors are used as a visual shorthand in explanations as they allow one to refer to the Internet as a definite object without having to explain the intricate details of its functioning. Clouds are the most common of abstract metaphors employed for this purpose in cloud computing and have been used since the creation of the Internet. Other abstract metaphors of the Internet draw on the fractal branching of trees and leaves, and the lattices of coral and webs, while others are based on the aesthetics of astronomy such as gas nebulas, and star clusters. Technical methods such as algorithms are often used to create huge, complex graphs or maps of raw data from networks and the topology of connections. The typical result of this process are visual representations of the Internet that are elaborate and visually striking, resembling organic structures. These artistic, abstract representations of the Internet have been featured in art galleries, sold as wall posters, used on book covers, and have been claimed to be a picture of the "whole" Internet by many fans. However, there are no instructions on how these images may be interpreted. The main function of these representations has sometimes been explained as a metaphor for the complexity of the Internet.