Op-Art Design is an artistic style that uses optical illusions to create visually stimulating works. The term 'Op-Art' is derived from the term 'optical art' and was popularized in the 1960s. One of the most common techniques used in Op-Art Design is moire, which is a visual effect created by overlapping two patterns with slightly different angles or sizes. Moire patterns are often used to create a sense of movement or depth in a work of art.