In spring I am gay in handso...In spring I am gay in handsome array; in summer more clothing I wear; when colder it grows I fling off my clothes; and in winter quite naked appear. What am I?
A linguistics professor was lecturing to his class one day. "In English," he said, "a double negative forms a positive. In some languages though, such as Russian, a double negative is still a negative."
"However," he pointed out, "there is no language wherein a double positive can form a negative."
A voice from the back of the room piped up, "Yeah. Right."