{
	package Iterator::Product;

	sub new
	{
		my $pkg = shift;
		@_ > 0 or die "$pkg->new() needs at least one iterator!";
		@_ > 1 or return shift;
		if ( @_ > 2 ) # reduce!
		{
			my $car = shift;
			@_ = ( $car, $pkg->new( @_ ) );
		}
		my $self = bless [@_], $pkg;
		$self->reset;
		$self
	}

	sub reset
	{
		my $self = shift;
		$self->[0]->reset;
		$self->_reset_inner;
		$self
	}

	sub _reset_inner
	{
		my $self = shift;
		$self->[1]->reset;
		$self->[2] = [ $self->[0]->value ];
		$self
	}

	sub value
	{
		my $self = shift;
		$self->is_exhausted and die "past end";
		$self->[1]->is_exhausted and $self->_reset_inner;
		( @{ $self->[2] }, $self->[1]->value, )
	}

	sub is_exhausted
	{
		my $self = shift;
		$self->[0]->is_exhausted && $self->[1]->is_exhausted 
	}
}