Altough the article is more "solids" oriented, you can get some useful information from msdn:
Just in case you do think this is not useful...
What is a line? You can simplify it as the edge of a surface
So if you want to draw a curve, you can get it simplifying a 3d object like an egg.
I mean, you can learn about the concepts of the "viewer/camera" position, the 3d space coordinates and so on, just don't pay attention to the surfaces and the textures.