Nesting levels in the source code - why do I have to use one level more than I thought?

[Petr Pařízek]

Hello,

I'm currently learning to use LilyPond. I've finally succeeded in writing a 
short piece of music but there's one thing I don't understand. In my source 
code, there was one line that said "\score {". In order it worked at all, I 
had to keep a single left brace { on the immediately following line, which 
meant that I later had to use a single right brace } on two consecutive 
lines.

To me, this seems like an additional level of nesting which I didn't think 
was necessary. So I wanted to know why it has to be there or why the 
compiling process fails if I don't keep that.

To be more specific, I'll quote a shortened version of my code to give you a 
better idea of what I'm talking about.

-----

\version "2.19.83"

\language "deutsch"

\score {

{

\key g \major

\time 4/2

<<

\relative \new Staff {

% The top voice goes here.

}

\relative \new Staff {

% The middle voice goes here.

}

\relative \new Staff {

% The bottom voice goes here.

}

> >

}

\layout { }

\midi { }

}

-----

Thank you for your suggestions or comments.

Petr