Custom note heads

[Helge Kruse]

Hello,

I've been asked to write some scores with custom note heads. These heads
are designed for beginners. I know that the Emmentaler font contains
some special heads but I don't know how to add new shapes.

I found this question at Stackoverflow
https://stackoverflow.com/questions/47341754/lilypond-custom-global-note-heads.
But this doesn't work, even if I add a file g.eps I get the error

Preprocessing graphical objects...C:/Program Files
(x86)/LilyPond-2.19-65/usr/share/lilypond/current/scm/stencil.scm:987:26:
In procedure list-ref in expression (list-ref bbox 2):
C:/Program Files
(x86)/LilyPond-2.19-65/usr/share/lilypond/current/scm/stencil.scm:987:26:
Wrong type argument in position 1: #f

How can I define my own custom note heads? I don't prefer EPS in this
field, can be any graphic file other format.

Or these other way round: At
http://lilypond.org/doc/v2.18/Documentation/notation/note-heads is a
Ez_numbers_engraver. Can this be modified to do the work?

Best regards
Helge