i expected to run into limits by working with a drawing program from 1986. i knew what i was getting into by using FullPaint. 2 colors only. No layers, can't resize the canvas (but the canvas is roughly the size of a sheet of print paper at the meager DPI that an Apple printer would use), limited undo depth.
what i was not expecting: the line tool can only draw in black. it cannot draw in patterns or white. so if i need a white line for any reason, i get to draw black lines around where i want the white line and then clean that up afterwards.
I'll get to share the piece where this is relevant soon, hopefully. because all things considered it is worth it.