Extrasensory perceptionExtrasensory perception , is the perception of some event or occurrence without there being any of the usual means of communication involved.
In 1934 biology Dr. Joseph Banks Rhine began the systematic investigation of the existence of telepathy, using a deck of 25 cards divided into 5 groups, each of the cards had a figure that was easy to remember, he then asked his assistants to try to predict. The cards were designed by one of his collaborators of the University of Duke named Zener.
Zener cards in general may be known for such simple graphics, there are five cards; one representing a star, another has three "waves" (wavy lines), one with a square, another has a circle and the other card would have a plus sign (addition: +).
Intuition is like a muscle that is developed with practice. It is not important how the cards look, or to act on impulse. Just try to relax and "see" through the eyes of your intuition, not through your physical eyes.