optical rubbing plates 6pcsEach plate in this pack of six features a unique optical illusion pattern that's perfect for adding texture and interest to your artwork. Simply place your drawing paper over the plate and rub with Zart drawing blocks, rubbing blocks, or crayons to transfer the intriguing designs onto your paper. These plates are perfect for artists of all ages and skill levels. Whether you're creating a fun art project, exploring the concept of optical illusions, or