You could be forgiven for not knowing about the artist Mart Meyer, who lives in Dallas and photographs what he sees almost moment by moment. Or for not having heard of the Chinese artist Ju Hu, who created a large-scale work examining the “malleable flow of time” as he camped out in an autumnal forest and tried to tape every fallen leaf back onto its tree. Almost certainly, you’re not acquainted with the art made by Rosalie Starr, who died in 1969 but whose sculptures were recently discovered in the attic of a Georgia boardinghouse, or the guerrilla feces paintings — quite beautiful, really — that have been popping up on the walls of public restrooms in New York and four other states and attributed to an artist known only as the East Coast Swiper.