Nice one. This statement in particular sums it up nicely:

Jung did not see the type preferences (such as introversion and extraversion) as dualistic, but rather as tendencies: both are innate and have the potential to balance.

I remember reading elsewhere that it'd be like drawing a line down the middle of a table of people's heights, so that those who were 5 feet 10 inches and under would be the "shorts" and those 5 feet 11 inches and taller would be the "talls".