Also known as “ESP cards,” this is a deck of 25 card using a repeating set of five simple geometric shapes (circle, square, wavy lines) used to test for ESP. The cards were designed in the 1930s by Karl Zener, a perceptual psychologist, for use by famed parapsychologist J.B. Rhine.
Readers, please enjoy this guest blog post by Tudorbeth, author of The Hedgewitch's Little Library, including the latest release in the series, The Hedgewitch's Little Book of Crystal Spells.
When people catch the crystal bug, they think they...