This second demonstration is a generalization of the first in that it allows you to choose an arbitrary line (y - y₀) = m(x - x₀) in the domain window. The two orange hotspots control the location of the point (x₀,y₀) and the direction of the line.

The graphs of the surface (x,y,f(x,y)) as well as the image of the line under f are shown in a separate window. A pink slicing plane has also been added.