Answer by taking a quote from the following article:

Porcupine Tree were an English rock band formed by musician Steven Wilson in 1987. The band began essentially as a solo project for Wilson, who created all of the band's music. By late 1993, however, he wanted to work in a band environment, bringing on frequent collaborators Richard Barbieri as keyboardist, Colin Edwin as bassist, and Chris Maitland as drummer to form the first permanent lineup. With Wilson as lead vocalist and guitarist, this remained the lineup until February 2002, when Maitland left the band and Gavin Harrison was recruited to replace him.

Porcupine Tree originated in 1987 as a collaborative hoax project by Steven Wilson and Malcolm Stocks. Partially inspired by the psychedelic/progressive bands of the 1970s, such as Pink Floyd, that had dominated the music scene during their youth, the two decided to form a fictional legendary rock band named The Porcupine Tree. The two fabricated a detailed back-story including information on alleged band members and album titles, as well as a "colourful" history which purportedly included events such as a meeting at a 1970s rock festival and several trips in and out of prison. As soon as he had put aside enough money to buy his own studio equipment, Wilson obliged this creation with several hours of music to provide "evidence" of its existence. Although Stocks provided a few passages of treated vocals and experimental guitar playing, his role in the project was mostly offering occasional ideas, with the bulk of the material being written, recorded, played, and sung by Wilson.  At this point, Porcupine Tree was little more than a joke and a private amusement, as Wilson was concentrating on his other project, No-Man, an endeavour with UK based singer and songwriter Tim Bowness. However, by 1989, he began to consider some of the Porcupine Tree music as potentially marketable. Wilson created an 80-minute-long cassette titled Tarquin's Seaweed Farm under the name of Porcupine Tree. Still showing the spirit of his joke, Wilson included an eight-page inlay which further revealed the hoaxed Porcupine Tree backstory, including references to fictitious band members such as Sir Tarquin Underspoon and Timothy Tadpole-Jones.  Wilson sent out copies of Tarquin's Seaweed Farm to several people he felt would be interested in the recordings. Nick Saloman, the cult UK guitarist better known as The Bevis Frond, had suggested that he send one to Richard Allen, a writer for the UK counter-cultural magazine Encyclopaedia Psychedelica and co-editor of the UK psychedelic garage rock magazine Freakbeat. Allen reviewed the tape in both magazines. Whilst he disliked some of the material, he gave much of it a positive review. Several months later, Allen invited Wilson to contribute a track to the double LP A Psychedelic Psauna that was being put together to launch the new Delerium label. Allen would also become the band's manager, press agent, and promoter until 2004, his role in marketing the band's image decreasing after The Sky Moves Sideways album. In the meantime, Wilson had continued to work on new material. In 1990, he released the Love, Death & Mussolini EP, issued in a very limited run of 10 copies. The EP remains an extremely rare, collectible piece. It was composed of nine at-the-time-unreleased tracks, as a preview for the upcoming second album. Later in 1990, Wilson released a second full-length Porcupine Tree cassette called The Nostalgia Factory, which further expanded Porcupine Tree's underground fanbase, although at this point, the band was still carrying on the charade of being 1970s rock legends. By this point, Porcupine Tree was entirely a solo project, with Stocks having amicably moved on to other activities.

Did they cover any of their songs?