In the 19th century, Hans Christian Andersen wrote the fairy tale of the princess and the pea. A prince wanted to marry a ‘real’ princess and, so, his mother designed a test. Princesses were invited to the house to sleep on a special bed of 20 soft mattresses piled on top of each other. Only one princess complained that the mattress was uncomfortable; something beneath the mattresses poked her all night. True enough, under the pile of 20 mattresses — enough to cause the princess discomfort — was just a single pea.

Illustration/Devdutt Pattanaik