Task: Question Answering
Input (English): Passage: After the 1994 release of The Downward Spiral, the live band embarked on the Self-Destruct tour in support of the album. Chris Vrenna and James Woolley performed drums and keyboards respectively, Robin Finck replaced Richard Patrick on guitar and bassist Danny Lohner was added to the line-up. The stage set-up consisted of dirty curtains which would be pulled down for visuals shown during songs such as "Hurt". The back of the stage was littered with darker and standing lights, along with very little actual ones. The tour debuted the band's grungy and messy image in which they would come out in ragged clothes slathered in corn starch. The concerts were violent and chaotic, with band members often injuring themselves. They would frequently destroy their instruments at the end of concerts, attack each other, and stage-dive into the crowd.The tour included a set at Woodstock '94 broadcast on Pay-per-view and seen in as many as 24 million homes. The band being covered in mud was a result of pre-concert backstage play, contrary to the belief that it was an attention-grabbing ploy, thus making it difficult for Reznor to navigate the stage: Reznor pushed Lohner into the mud pit as the concert began and saw mud from his hair going into his eyes while performing. Nine Inch Nails was widely proclaimed to have "stolen the show" from its popular contemporaries, mostly classic rock bands, and its fan base expanded. The band received considerable mainstream success thereafter, performing with significantly higher production values and the addition of various theatrical visual elements. Its performance of "Happiness in Slavery" from the Woodstock concert earned the group a Grammy Award for Best Metal Performance in 1995. Entertainment Weekly commented about the band's Woodstock '94 performance: "Reznor unstrings rock to its horrifying, melodramatic core--an experience as draining as it is exhilarating". Despite this acclaim, Reznor attributed his dislike of the concert to its technical difficulties. 
Question: What did the back stage have very little of?
Output (English): lights.