Similarly the twin sign of this jar sign is what is called the arrow sign, or the lance sign. It is a twin functional in the sense that both these signs occur at the end, almost always after other signs which may represent names, so therefore it is another type of grammatical suffix. But one view is, like the one presently held by Parpola, that one is genitive and one is dative. I think this is unlikely because in which case you must occasionally have this symbol following the same names. But the use of the jar sign and the arrow sign are generally mutually exclusive; where the one occurs, the other never does, showing they are integrally connected, semantically related to the names which precede those symbols, which would rule out an explanation like a case ending. However, the position is that this is all still in the realm of speculation. No one has any hard evidence. I have suggested that the jar sign represented the elite who later developed the myth of the jar-born sages and jar-born rulers. I am not suggesting that the myth existed, even in the Indus civilization, but it developed into a myth later.
Let me give you a pictorial example. Let us assume that English is a pictorial language and all English gentlemen who called themselves "Squire" wrote a square sign after their names. Then, centuries later, the myth would develop about English gentlemen and their connection with squares, that their houses were squares, or their temples were square. In the long development of the Indian civilization, the jar sign acquired a myth, so when I deal with it I am looking not at the jar sign as it was understood in the Indus Valley but as it was understood centuries later. The survival would be among the same groups. In other words, if the Vedic rishis claimed special affinity to the jar then the Harappan priests had something to do with the jar, broadly speaking. It is not a linguistic argument, it is a cultural argument. Similarly the arrow sign may have to do with warriors, and a sign with shwoing a plain simple man may be a servant.