Ever know a cat that didn't want to get on the other side of a closed door?
While trying to avoid the plague of 1666, Isaac Newton decamped to
Woolsthorpe. While there, he developed the Calculus but his work was
continually interrupted by his cat fussing to be on the other side of the
door to Newton's study.
Newton summoned a carpenter and had him cut a hole in the door which Newton
covered with a piece of canvas.
So, in addition to inventing the Calculus, discovering the Law of Universal
Gravitation and the Three Laws of Motion, inventing the first refracting
telescope, and being responsible for many other scientific advancements, we
can all be grateful for his contribution to human and animal tranquillity:
THE CAT DOOR
Thank you Sir Isaac.