producer Skrillex was an influence when writing one of the final two tracks on the album – "The 2nd Law: Unsustainable". He also stated that the song "Follow Me" was written about his newborn son, Bingham Bellamy. The song was produced by electronic music trio Nero. Bassist Chris Wolstenholme wrote two songs for the album about his battle with alcoholism – "Save Me" and "Liquid State" – and provided lead vocals on both tracks, thus marking the first time Wolstenholme sang lead vocals on a Muse song. Bellamy revealed that during the recording of The 2nd Law he was reading the novel World War Z, which became a major influence on the album, especially the tracks "The 2nd Law: Isolated System" and "Survival". "The 2nd Law: Isolated System" was featured in the film adaptation of the novel. Packaging The name "The 2nd Law" references the second law of thermodynamics, which is quoted in the track "Unsustainable" as follows: All natural and technological processes proceed in such a way that the availability of the remaining energy decreases. In all energy exchanges, if no energy enters or leaves an isolated system, the entropy of that system increases. Energy continuously flows from being concentrated, to becoming dispersed, spread out, wasted, and useless. New energy cannot be created and high-grade energy are being destroyed. An economy based on endless growth is unsustainable. The album's cover art, taken from the Human Connectome Project, represents the map of the human brain's pathways, "tracking the circuits in our heads and how we process information with bright, neon colors." The artwork was subsequently used by Muse in a social Connectome Project on 21 September 2012. As more fans joined the online project, the album art was built, representing the network of the neurons within the brain. As the album art branched and more fans joined the network, incremental segments of the album track "The 2nd Law: Isolated System" were released. The album was released as a digital download, CD, CD+DVD (with The Making of The 2nd Law and bonus feature), and vinyl. A deluxe edition box set of The 2nd Law included a CD, DVD, double vinyl and three posters. Promotion On 6 June 2012, Muse released a trailer for The 2nd Law with a countdown on the band's website suggesting a 17 September release date. The trailer, which included dubstep elements, was met with mixed reactions from