In 1990 and 1991, the KLF also remixed tracks by Depeche Mode ("Policy of Truth"), the Moody Boys ("What Is Dub?"), and Pet Shop Boys ("So Hard" from the "Behaviour" album, and "It Must Be Obvious"). Pet Shop Boy Neil Tennant described the process: "When they did the remix of 'So Hard', they didn't do a remix at all, they re-wrote the record ... I had to go and sing the vocals again, they did it in a different way. I was impressed that Bill Drummond had written all the chords out and played it on an acoustic guitar, very thorough."