Fixed bolded lines appearing, thanks to @arocho
Beginning work with setting up the isometric diagram - iterating on anti diagonals of the level data is the first step, and it works.
There is an error in drawing.  As I iterate on the level data's anti diagonals, I need to be drawing in a standard grid fashion on-screen, to be able to do offsets properly, and all that.  But it's not doing it properly, probably because as I iterate on the anti diagonal, I am not accounting for x and y offsets on the grid properly.
Committing and pushing changes to figure out errors on a different computer.