I want to plot the following flow in math softwares but I don't know its algebraic equation! Any hint would be greatly appreciated. (image from Milnor's Topology from differential viewpoint)
Edited: A function with two asymptotic line (at least, a function with one slanted and one horizontal asymptotic line), and similar to above image, suffices. e.g. A function with four connected components and slant asymptotic $y=-x$ and horizontal asymptotic $y=0$.