begin flex[10:-10]int je;
      int num_fields = 3;
      assert (UPB je = -10 AND LWB je = 10 AND ELEMS je = 0);

      [1:num_fields][1:num_fields]string fields;
      for i to num_fields
      do for j to num_fields
         do assert (fields[i][j] = "") od
      od
end