Peter,
> the addition of foot-tapping visuals beneath musical scores. [...]
Thanks for the images, however, they don't convince me from a
typographical point of view. Please remember that LilyPond is
primarily a tool for typesetting music in high quality – your images
are not of such a high quality, and it is difficult to me to decide
whether this feature is something you've cooked up or whether there
really exist scores with such foot-tapping visuals.
If this is your personal ad-hoc notation, I fear there will be zero
support from anyone to ever implement it. You would have to do this
by your own. Otherwise please present *typeset*, high-quality scores
that we can use to illustrate a new issue.
Werner