Yes, there is a real world out there, and you perceive events that occur around you, however incorrectly or incompletely. But you have never actually lived in the real world, in the sense that your experience never matches physical reality perfectly. Your brain instead gathers pieces of data from your sensory systems—some of which are quite imprecise or, frankly, wrong. Soon after placing the ad in American Way, Baccei says he was jolted awake in the middle of the night with an epiphany. “I realized I was selling the wrong thing. People wanted more autostereograms, and they’d buy it.” Baccei mortgaged his house, and with the help of Smith started Magic Eye as a sub-company under one of his existing businesses, N.E. Thing Enterprises. In 1991, N.E. Thing Enterprises began working with Tenyo Co., Ltd, a Japanese company know for selling an array of magic products. This relationship led to the christening of Magic Eye. “We called it Magic Eye because it translated well to Japanese—and because it had ‘magic’ in the name,” Smith recalled. At the time, Tenyo was selling Magic Eye autostereogram posters, postcards, and other retail products. When the company released the first three Magic Eye books later that year, Magic Eye became an overnight sensation.

Kreiner WA. Algebraic functions describing the Zöllner illusion. Open Access Repositorium der Universität Ulm. 2012. doi:10.18725/OPARU-2597 An autostereogram is a single-image stereogram (SIS), designed to create the visual illusion of a three-dimensional (3D) scene from a two-dimensional image in the human brain. An ASCII stereogram is an image that is formed using characters on a keyboard. Magic Eye is an autostereogram book series.A window is formed in the shape of a trapezium. It is often hung and spun around to provide the illusion that the window rotates through less than 180 degrees.

The Jastrow illusion is an optical illusion discovered by the American psychologist Joseph Jastrow in 1889.

He taught science and creative writing in elementary and secondary schools and was chair of the science department at a junior high school in the New York City public school system before leaving to become a full-time writer. "I haven't really given up teaching," he says, "and I suppose I never will, not as long as I keep writing and talking to kids around the country and the world." Like many optical illusions, different theories have been proposed to explain exactly why this happens. Sakiyama T., Sasaki A., Gunji YP. Origin of Kanizsa triangle illusion. In: Rhee SY., Park J., Inoue A. (eds) Soft Computing in Machine Learning. Advances in Intelligent Systems and Computing, vol 273. Springer, Cham; 2014. doi:10.1007/978-3-319-05533-6_10 In Sander's parallelogram (1926) the diagonal line bisecting the larger, left-hand parallelogram appears to be considerably longer than the diagonal line bisecting the smaller, right-hand parallelogram, but is in fact the same length. The Pulfrich effect is the effect that covering one eye with transparent but darkened glass can cause purely lateral motion to appear to have a depth component even though in reality it doesn't; even a completely flat scene such as one shown on a television screen can appear to exhibit some three-dimensional motion, but this is an illusion due to the fact that darkening the scene for one eye causes the photoreceptors in that eye to respond more slowly.