Animals originally came out in 1977 and was Pink Floyd's tenth studio album. Roger Waters used the animals from George Orwell's Animal Farm as an image of British society: dogs as predatory businessmen, pigs as those in power and sheep as the compliant masses. Three long pieces — "Dogs", "Pigs (Three Different Ones)" and "Sheep" — are framed by the two short acoustic parts of "Pigs on the Wing". The album sounds harder and barer than its predecessors, with extended guitar work from David Gilmour and heavy use of synthesizers and vocoder. The sleeve, showing an inflatable pig above Battersea Power Station in London, became one of the best-known images in rock. This edition is an LP on black vinyl.