https://bingo.cdyn.com/ppm/3-in-line_poor.jpg
it's pretty much readable. Probably a candidate for redraw in a vector program like inkscape if a good schem is not available from the usual suppliers.
the source scan is a 600dpi uncompressed tif and is around 1.3GB. If someone wants that to take a shot at cleanup or redraw so they can send to ipdb pm me.