sub spaceship {
  (0 <=> $_[0]) == (0<=> $_[1]);
}

sub mult {
  $_[0]*$_[1] > 0;
}

sub anchor {
  if ($_[0] > 0) {
    if ($_[1] > 0) { # both pos
      return 1
    }
  } elsif ($_[0] < 0) {
    if ($_[1] < 0) { # both neg
      return 1
    }
  }
  return 0;
}