Saddle Point

Note the nipple points and the cleve point.

In mathematics, a saddle point is a point in the domain of a function that is a stationary point but not a local extremum. The name derives from the fact that the prototypical example in two dimensions is a surface that curves up in one direction, and curves down in a different direction, resembling a saddle or a mountain pass. In terms of contour lines, a saddle point in two dimensions gives rise to a contour that appears to intersect itself.

Read more about Saddle Point:  Mathematical Discussion, Other Uses

Famous quotes containing the words saddle and/or point:

    Oh, give me again the rover’s life—the joy, the thrill, the whirl! Let me feel thee again, old sea! let me leap into thy saddle once more. I am sick of these terra firma toils and cares; sick of the dust and reek of towns.
    Herman Melville (1819–1891)

    Consider a man riding a bicycle. Whoever he is, we can say three things about him. We know he got on the bicycle and started to move. We know that at some point he will stop and get off. Most important of all, we know that if at any point between the beginning and the end of his journey he stops moving and does not get off the bicycle he will fall off it. That is a metaphor for the journey through life of any living thing, and I think of any society of living things.
    William Golding (b. 1911)