Interesting facts:
• In 1922, Matthew Luckiesh wrote an optical illusions book titled - Visual Illusions: Their Causes, Characteristics and Applications. It was probably the first book to comprehensively cover the topic of Optical Illusions, or Visual Illusions, as they were called then.
• An illusion involving temperature can be seen if you touch a piece of silverware at a dinner setting and touch the table cloth. You think that the silverware is cooler than the cloth when, in fact, they are both at room temperature.