E-Mail IMAGE: Photo of a metamaterial composed of a pattern of resonators. The defect appears as a pentagon in an otherwise regular array of circuit elements. view more Credit: Kitt Peterson Real-world materials are usually messier than the idealized scenarios found in textbooks. Imperfections can add complications and even limit a material's usefulness. To get around this, scientists routinely strive to remove defects and dirt entirely, pushing materials closer to perfection. Now, researchers at the University of Illinois at Urbana-Champaign have turned this problem around and shown that for some materials defects could act as a probe for interesting physics, rather than a nuisance.