#(define mydrums
   '((bassdrum () #f -5)
     (snare () #f 0)
     (lowtom cross #f -2)
     (hihat () #f 3)))
	    
#(define parallelogram
   (ly:make-stencil (list 'embedded-ps
      "gsave
       currentpoint translate
       newpath
       0 0.25 moveto
       1.3125 0.75 lineto
       1.3125 -0.25 lineto
       0 -0.75 lineto
       closepath
       fill
       grestore" )
      (cons 0 1.3125)
      (cons 0 0)))

#(define (make-drum-note dt dur st)
   (make-music
     'SequentialMusic
     'elements
       (list
	 (make-music
	   'ContextSpeccedMusic
	   'context-type 'Bottom
	   'element
             (make-music
               'OverrideProperty
               'pop-first #t
               'grob-property-path (list (quote stencil))
               'grob-value st
               'once #t
               'symbol 'NoteHead))
	 (make-music
	   'EventChord
	   'elements
	     (list
	       (make-music
	         'NoteEvent
	         'drum-type dt
		 'duration dur))))))
		       
#(define (custom-notehead mus)
   (if (eq? (ly:music-property mus 'name) 'EventChord)
   (let* ((e (car (ly:music-property mus 'elements)))
	  (dur (ly:music-property e 'duration))
	  (dt (ly:music-property e 'drum-type)))
	 (case dt
	   ((bassdrum) (set! mus (make-drum-note dt dur parallelogram)))
	   ((hihat) (set! mus (make-drum-note dt dur parallelogram))))))
   mus)
	 
customHeads =
#(define-music-function (parser location music) (ly:music?)
   (music-map (lambda (x) (custom-notehead x)) music))

<<
\new DrumStaff \with { drumStyleTable = #(alist->hash-table mydrums) }
\new DrumVoice \drummode
{
	\customHeads { bd8 sn toml hh }
}
>>