\version "2.11.35"
\header {
  title = "Available X11 colors with examples"
}
#(ly:load "x11-color.scm")

#(define-markup-list-command (listcolors layout props) ()
  (interpret-markup-list layout props
    (map (lambda (colorspec) 
      (markup #:with-color (x11-color (car colorspec)) 
              #:filled-box (cons -0.5 10) (cons -1 3) #'1 
              (symbol->string (car colorspec))
              )
    ) x11-color-list )
  )
)

\markuplines \column-lines \listcolors