An interesting property of hyperbolic geometry follows from the occurrence of more than one parallel line through a point "P": there are two classes of non-intersecting lines. Let "B" be the point on "l" such that the line "PB" is perpendicular to "l". Consider the line "x" through "P" such that "x" does not intersect "l", and the angle θ between "PB" and "x" counterclockwise from "PB" is as small as possible; i.e., any smaller angle will force the line to intersect "l". This is called an asymptotic line in hyperbolic geometry. Symmetrically, the line "y" that forms the same angle θ between "PB" and itself but clockwise from "PB" will also be asymptotic. "x" and "y" are the only two lines asymptotic to "l" through "P". All other lines through "P" not intersecting "l", with angles greater than θ with "PB", are called ultraparallel (or disjointly parallel) to "l". Notice that since there are an infinite number of possible angles between θ and 90 degrees, and each one will determine two lines through "P" and disjointly parallel to "l", there exist an infinite number of ultraparallel lines.