Noteheads using make-connected-path-stencil

[Andrew Bernard]

Using LSR 891 as a base pattern, how can you fill the path with a
colour, such as white?

Andrew

%======

\version "2.21.6"

tri =
#(make-connected-path-stencil
  '(;; path coordinates
     (-0.5 0)
     (0 -1)
     (0.5 0)
     (0 0)
     )
  0.1 ;; line thickness
  1  ;; X-axis scaling factor
  1  ;; Y-axis scaling factor
  #f  ;; automatically connect path to origin point? (0 0)
  #f)  % filled path?

{
  \override NoteHead.stencil = \tri
  \override NoteHead.stem-attachment = #'(1 . 0.7)
  e'4 f' g' a'
}