Cabinets of curiosities challenged human perception on all levels, often stimulating and even upsetting the senses. A common part of these early collections were optical devices and illusions originally developed by Renaissance Italian artists, including Leonardo da Vinci, as part of their experiments with perspective. Anamorphic images- a term derived from the Greek for "transformation"- were stretched in various ways according to precise mathematical formulas. These strange lines and blobs of color were unintelligible except from particular vantage points where the image would snap into view to reveal meaningful and often humorous or surprising pictures. By the seventeenth and eighteenth centuries, anamorphic images had become useful tools for teaching math but also amusing parlor tricks. Loca Miraculi is an exhibition at the Milwaukee Art Museum.