Catch the monkey
In India, hunters had a proven way of catching monkeys. A half coconut would be hollowed out and a hole made that was only large enough to let a monkey’s hand pass through. The coconut was then pinned to the ground and tempting food placed beneath. A monkey would approach, intent on getting hold of the food beneath the coconut, but alas as soon as it grasped the food in its fist it found itself unable to pull its hand and the food free of the coconut. Imprisoned it would stay, caught by its own unwillingness to open its fist.