LOS ANGELES (AP) – Pink Floyd is asking fans to help create a dark side to the moon on their website. To mark the 40th anniversary of the release of “Dark Side of the Moon” on Sunday, Pink Floyd is asking fans to share their thoughts on Twitter with the hashtag #DarkSide40. The combined messages will be used to turn the moon dark on PinkFloyd.com. Storm Thorgerson, who designed the “Dark Side of the Moon” cover, is revealing new prism designs on the band’s website, with a new one each day until Sunday. The 14 designs will form a celebratory poster that will be available for download.