Most of us, at one time or another, have seen performances by horses trained to do simple maths. The number of times the horse clops his hoof is the answer to the addition or subtraction problem the trainer has presented.

Well, back in the day, there was one horse so good at this that he soon outgrew simple addition. He mastered the multiplication tables with ease, then proceeded to learn long division. It wasn't long before he was solving algebraic equations. But he met his match when confronted by analytic geometry. In fact, when exposed to coordinates, he was so baffled that he refused to ever do maths again.

And thus originated the common expression warning against the folly of putting Descartes before the horse.