Here's one for you, Boathail! My brother was on holiday abroad and came across an 8in circular saw blade at a garage sale. (It's the sort of thing he does on holiday!). Each alternate tooth pointed in the opposite direction to its neighbour. He was given an explanation, but can you guess the reason for it? ;-)
Yes, heathfield. It�s a bi-polar blade. It can be used in the north and south poles, with no ill effects. The valency of the differential divided by the diameter of the blade gives us its integral logarithm. Multiply this by its cosine shows its stellicullar structural integrity. Which by definition is the angular declination of its original structural integrity. Of which I have none, because I just made this all up!