\header{
filename = "preludes-3.ly";
-title = "3";
-opus = "BWV 999";
-% piece = "\\numfont 3";
-piece = "3";
% Pr"aludum in C Moll f"ur Laute
% blz 16
% Six Petits Preludes`
\grand_staff
\paper{ \a4 }
\midi{ \tempo 4 = 100; }
+ \header{
+ opus = "BWV 999";
+ piece = "3";
+ }
}