sub outer {
 ...
 sub inner {
 }
 ...
}

##</code><code>##

{
  my $hidden_data;
  sub one {
   ... 
   access the $hidden_data;
   ...
  }
  sub two {
   ... 
   access the $hidden_data;
   ...
  }
}

##</code><code>##

sub outer {
  my $lexical = ...;
  ...
  my $inner = sub { ...; access $lexical; ... };
  ...
  $inner->(...);
  #or even
  return $inner;
}

##</code><code>##

my $hash{key} = ...; # is illegal
local $hash{$key} = ...; # is legal
#on the other hand
my $x = 1;
{
  my $x = 2; # is legal, a new variable was created, outer $x is not visible
}
#while
my $x = 1;
{
  local $x = 2; # is illegal. Can't localize a lexical variable

##</code><code>##

our $variable = 15;

{
 local $variable = 33;
 sub one {
  print "in one(): \$variable = $variable\n";
 }
 sub two {
  print "in two(): \$variable = $variable\n";
 }
}

one();
two();

$variable = 99;

one();
two();

##</code><code>##

our $variable = 15;

{
 my $variable = 33;
 sub one {
  print "in one(): \$variable = $variable\n";
 }
 sub two {
  print "in two(): \$variable = $variable\n";
 }
}

one();
two();

$variable = 99;

one();
two();