use Readonly
Readonly my $FOO => 10;
Readonly my @GAMES => ( 'tennis', 'crocket', 'crazy eights' );
Readonly my %NUMBERS 
    => ( consonents => [ qw( b c d f g h j k l m n p q r s t v w x z) ],
         vowels     => [ qw( a e i o u y ) ],
       );