sub remove_card {
  # usage: $caller->remove_card()
  # removes top card of pile, returning its value

  my $self = shift;
  if($self->num() > 1) {
      # I've worked with many alterations of this, and this
      # seems (I repeat *seems*) to be what I want
    $self->cards( $self->cards()->[1..$self->num()-1] );
  } else { $self->cards([]) }
}