In U.S. patent 1,471,465 Hinton wrote on page 3, "Again and importantly, the monkey instinct strong in all human beings and perhaps more clearly displayed in children, makes climbing a sport to which children enthusiastically take, by a psychology about the same as that of a kitten at play with a ball, which of course is practice for hunting."
In U.S. patent 1,488,244 Hinton wrote on page 3, "I have found, however, that children seem to like to climb through the structure to some particular point, and there swing head downward by the knees, calling back and forth to each other, a trick which can be explained of course only by the monkey instinct", and on page 4 he wrote, "I make considerable point of the great strength of the structure, as this is important. Thus most persons have seen a monkey in a zoo, seize the bars of his cage with hands and feet and throw his body violently back and forth, other monkeys following suit. Children in the structure I have erected do the same thing, apparently unconscious of any imitation of monkeys. It can be appreciated that with twenty-five or thirty heavy boys doing this, the strains on the structure are very great."
