You can see the opponent relationships between red and green, and blue and yellow. View the four-color patch afterimage stimuli below for 30 seconds. Then remove the color stimuli by looking away and staring at blank white wall. When you fixate at the dot in the center of the field you should notice that the original colors are all reversed - where you saw red it is now green and vice versa. Likewise for blue and yellow.
Las líneas horizontales parecen estar en pendiente, pero mira el tiempo suficiente y verás que son paralelas entre sí
Ten (Mostly) New Illusions To Kick Start Your Brain in the Morning: Admittedly, some of these illusions are a little old. In fact, there's a good chance your grandparent's grandparents were befuddled by the rabbit/duck illustration. But there are still plenty of newer illusions that will leave your wondering why the human brain can be so easily fooled.