use strict;
use warnings;

package Goo;
my $x=100;
print "package=", __PACKAGE__, " x=$x\n";

package Boo;
{
  my $x=200;
  print "package=", __PACKAGE__, " x=$x\n";
}

package Foo;
print "package=", __PACKAGE__, " x=$x\n";

#outputs
package=Goo x=100
package=Boo x=200
package=Foo x=100