sub insert_after_first {
    return if @_ < 3;
    my ( $elem, $new, $front ) = splice @_, 0, 3;
    return ( $front,
             $front eq $elem
             ? ($new, @_ )
             : insert_after_first( $elem, $new, @_ )
           );
}

##</code><code>##

sub insert_after_first {
    return if @_ < 3;
    my ( $elem, $front ) = (splice(@_, 0, 1), splice(@_, 1, 1));
    return ( $front,
             $front eq $elem
             ? @_
             : insert_after_first( $elem, @_ )
             );
}

##</code><code>##

sub insert_after_first {
    return if @_ < 3;
    my $front = splice(@_, 2, 1);
    return ( $front,
             $front eq $_[0]
             ? @_[1..$#_]
             : &insert_after_first
	   );
}