What is this warning? “no viable initial configuration found: may not find good beam slope”

[Harold Hausman]

Hello,

First, thanks for Lilypond. It's patently amazing and I am super-grateful for it.

This code:

 - https://gist.github.com/harold/0b945bdfea789d05a92c6b2fe29b35ee

Produces this output when compiling:

    $ lilypond test.ly 

    GNU LilyPond 2.18.2

    Processing `test.ly'

    Parsing...

    Interpreting music...

    Preprocessing graphical objects...

    Finding the ideal number of pages...

    Fitting music on 1 page...

    Drawing systems...

    test.ly:27:15: warning: no viable initial configuration found: may not find good beam slope

          \lh b16 

                  c'

    Layout output to `test.ps'...

    Converting to `./test.pdf'...

    Success: compilation successfully completed

And this generally good looking graphical output:

 - https://i.stack.imgur.com/1AJPp.png

My question is about the "warning":

 - "no viable initial configuration found: may not find good beam slope"

Is the warning having an ill effect? What causes it? Is it possible to get better beam slopes? To my eyes, the fourth beat beams maybe should be going up instead of down (but what do I know?).

Is my code a good way to express this musical idea in Lilypond? I am 100% a Lilypond neophyte, is there a better way?

Also, this is my first post to this list, sorry if I have violated any mores of this community.

Warmly,

-Harold