on the vinyl version of the album, the time length for "expressway to yr. skull" was indicated by the infinity symbol (∞); the final moment of the song featured a locked groove that repeatedly plays the last few seconds of a song, making it theoretically endless. the cd version added a bonus track: the band's cover of the kim fowley tune "bubblegum". according to watt, he and shelley played the basic rhythm track over the actual fowley record, which was afterwards removed when the other members added their parts.