Art is the product or process of deliberately arranging items (often with symbolic significance) in a way that influences and affects one or more of the senses, emotions, and intellect.  The meaning of art is explored in a branch of philosophy known as aesthetics, and even disciplines such as history and psychology analyze its relationship with humans and generations. Optical illusion art requires math ingenuity, technical skills and meticulous planning. Because it manipulates the rules of perception, a viewer trying to decipher such a painting may observe movement, hidden images, three-dimensional forms, and other simulation.