This was taken from the Bonhomme Richard ANCRE drawings. The drawing is a cross section, as if the ship were cut in half along the centerline. The screen shapes are what is known as a hatch. Hatches are used to denote a cut edge (as in you are looking through the material). The screen hatch is the wood material of the main steps, while the spaced lines at 45° are the keel, hogging piece, frames, and keelson. As for the sources used to make the ANCRE drawings, someone else who knows better should be able to say, but from what I have heard ANCRE is very reliable.