What happens when musicians from multiple progressive-rock bands with cult followings form their own group? Box of Shamans answers that question with a loose concept album about delusions, Belief and Illusion. Featuring past and present members of such bands as Heliopolis, Mars Hollow and Ten Jinn, this just-as-oddly-named power trio borrows freely from classic prog acts like Rush and Yes. With songs ranging in length from 82 seconds to 10-and-a-half minutes, Belief and Illusion doesn’t always sound finished. Surprisingly, the longer pieces are the more complete ones. “The Search,” a tour de force with intricate rhythms and compelling contrapuntal vocals in the vein of Gentle Giant and Spock’s Beard, suggests this band’s full potential once it sharpens its focus. Belief and Illusion won’t turn newcomers into prog fans, but Box of Shamans is a worthy buzz band for fans of the genre.