Thin bars

[Fibonacci Prower]

Hello,

Simply put, I find the default bars in lilypond too thick - whether
they be the bars automatically put between beats, or the ones inserted
by using \bar "something".
Is there any way to make them thinner?

--
$0='!/msfQ0yjoV!fe!sfldbi!psup!pmpT'x19xor print+map{("\e[7m \e[0m",
chr ord(chop$0)-1)[$_].("\n")[++$i%72]}split//,unpack'B*',pack'H*',(
$P='F'x18)."8186078739E1F0F0E19FCF333319CCE6667383CF0733099E67E7F39"
."FCF3333218067E7F39FCF3333319E6666739F860787399E70F0E1$P"#Perl rulz