sub cull (&\@) {
  my ( $test, $array ) = @_;
  my @culled;
  for ( my $i = $#$array; $i > -1; --$i ) {
    local $_ = $array->[ $i ];
    unshift @culled, splice @$array, $i, 1 if $test->();
  }
  return @culled;
}