cmpthese -1,{
    d => q[ my @d = '0001' .. '1000'; ],
    c => q[ my @c = '0001' .. '1000'; $c[ $_ ] += 0 for 0 .. $#c; ],
    a => q[ my @a = '0001' .. '1000'; $_ += 0 for @a; ],
    b => q[ my @b = '0001' .. '1000'; my @new; push @new, $_ + 0 while defined( $_ = shift @b ) ],
};