Kassite kudurrus signify many Indus Script hieroglyphs/hypertexts as sacred memories from the Script tradition. This hypothesis is validated in this monograph from the evidence of symbols used on about 50 kudurrus from the Bronze Age Ancient Near East sites including Susa.
Background note on cultural contacts between Indo-Aryan and Kassites/Mitanni
"That there was a migration of Indo-European speakers, possibly in waves, dating from the 2nd millennium bce, is clear from archaeological and epigraphic evidence in western Asia. Mesopotamia witnessed the arrival about 1760 bce of the Kassites, who introduced the horse and the chariot and bore Indo-European names. A treaty from about 1400 bce between the Hittites, who had arrived in Anatolia about the beginning of the 2nd millennium bce, and the Mitanni empire invoked several deities—Indara, Uruvna, Mitira, and the Nasatyas (names that occur in the Rigveda as Indra, Varuna, Mitra, and the Ashvins). An inscription at Bogazköy in Anatolia of about the same date contains Indo-European technical terms pertaining to the training of horses, which suggests cultural origins in Central Asia or the southern Russian steppes. Clay tablets dating to about 1400 bce, written at Tell el-Amarna (in Upper Egypt) in Akkadian cuneiform, mention names of princes that are also Indo-European."
One suggestion is that Kassites are Kāśyas, the founders of Kāśī, the region of Vāranāsi first mentioned in the Paippalada version of the Atharvaveda. "...some Kassite king names, which are evidently Indic (for example: Shuriash = Surya, Maruttash = Marut, Inda-Bugash = Indra-Bhaga), we can understand that they were also influenced by Hurrians or perhaps by the Medes, that in a later period were the owners of the Zagros and appointed the Magi as their priestly caste. Such kind of alliances between Sumerian/Subarian tribes and Indo-Aryan peoples seem to have been very common, and even achieved in taking control of the whole Mesopotamia during that period: the Kassite kingdom in the south preceded about 90 years the Mitanni kingdom in the north, and survived it for other 90 years." http://www.imninalu.net/myths-Huns.htm "The fifth king among the Kassite dynasty took the name Abirattas’ (abhi-ratha ‘facing chariots (in battle)’. (T. Burrow, The Sanskrit Language , London, Faber and Faber, 1955)...Mr. Kak in his paper makes a number of points:
a) Following the collapse of the Sarasvati – river based economy around1900 BC, groups of Indians might have moved West and that might explain the presence of the Indic Kassites and the Mitanni in West Asia .
b) The old Vedic religion survived for a fairly long time in corners of Iran. The evidence of its survival comes from the daiva-inscription of Khshayarshan (Xerxes) (486-465 BC).
c) The ruling groups-Kassite and Mitanni – represented a minority in a population that spoke deferent languages. They, however, remained connected to their Vedic traditions. They were neighbors to the pre-Zoroastrian Vedic Iran . In addition, there were other Vedic religion groups in the intermediate region ofIran which itself consisted of several ethnic groups.
d) As per the Mitanni documents , the pre-Zorastrian religon in Iran included Varuna. Since Mitra and Varuna are partners in the Vedas, the omission of Varuna from the Zoroastrian lists indicates that Zarathushtra might be from the borderlands of the Vedic world where the Vedic system was not fully in place. e) The pre-Zoroastrian religion of is clearly Vedic. Zarathushtra’s innovation lay in his emphasis on the dichotomy of good and bad The Zoroastrian innovations did not change the basic Vedic character of the culture in Iran. The worship ritual remained unchanged, as was the case with basic conceptions related to divinity and the place of man."
https://sreenivasaraos.com/2012/08/31/the-rig-veda-and-the-gathas-revisited/comment-page-1/
There is a reference to a wheelwright (chariot-maker) in a Susa sculptural frieze with Indus Script hypertext expressions.
kātī, 'spinner' rebus: khātī 'wheelwright'. The fish is ayo 'fish' rebus: aya 'iron' (Gujarati)ayas 'alloy metal' (R̥gveda) baṭa 'six' rebus: bhaṭa 'furnace'. kola 'tiger' (see tiger paws of stools) rebus: kol 'working in iron'.
A fragment called 'spinner' is a relief of bitumen mastic from Susa. Young woman spinning and servant holding a fan. Fragment of a relief known as "The spinner". Bitumen mastic, Neo-Elamite period (8th century B.C.–middle of the 6th century B.C.). Found in Susa. F ig. 141 La Fileuse (Lady spinning) Bitumen compound. H 9.3 cm. W. 13 cm. Neo-Elamite period, ca. 8th -7th century BCE. Susa. Sb 2834 (Louvre Museum) Excavated by J. de Morgan. Sb2834.
This relief has remarkable Indus Script hieroglyphs and has been called a Rosetta Stone of Indus Script cipher. One characteristic feature of the hieroglyph-multiplex is the use of a numerical semantic determinative. Six round objects are shown on a fish. In this pictorial, fish is a hieroglyph. Numeral six is a hieroglyph. Together, the Indus Script cipher is: aya 'fish' Rebus: ayas 'metal' goṭ 'round' Rebus: khoṭ 'alloy' PLUS bhaṭa 'six' Rebus: bhaṭa 'furnace.' Thus, the hieroglyph-multiplex proclaims the message: aya khoṭ bhaṭa
'metal (alloy) furnace'. Similar examples of the significance of 'six' numeral as a cipher from Ancient Near East are presented to signify phrases such as: meḍ bhaṭa 'iron furnace'. करडा karaḍā bhaṭa 'hard alloy furnace'.
Ancillotti demonstrate that Kassite is originally an Indo-Aryan language. (A. Ancillotti, La lingua dei Cassiti, Milan, 1981.) (Encyclopaedia Iranica does not find this convincing).
http://www.iranicaonline.org/articles/kassites However, Indo-Iranian immigrations are noted:"Early impact of an immigrating Indo-Iranian group is suggested by a small, but linguistically and culturally significant, number of terms. These include šuriias “sun god,” Old Indo-Aryan *sūrya, and the personal name Abi-rattaš, with Indo-Iranian *ratha “chariot,” which reflects the new technology of warfare. Otherwise the linguistic affiliation of these peoples is uncertain." http://www.iranicaonline.org/articles/iran-vii5-kassite The association of Kassites and Indo-Aryans is clearly related to horse-riding and riding chariots (as noted also in the Indo-Aryan manual on horse-trainining by Kikkuli). "Kikkuli was the Hurrian "master horse trainer" (assussanni, virtually Sanskrit aśva-sana-) of the land Mitanni" (LÚA-AŠ-ŠU-UŠ-ŠA-AN-NI ŠA KUR URUMI-IT-TA-AN-NI) and author of a chariot horse training text written in the Hittite language, dating to the Hittite New Kingdom (around 1400 BCE). The text is notable both for the information it provides about the development of Indo-European languages and for its content...CTH 284 consists of four well preserved tablets or a total of 1080 lines. The text is notable for its Mitanni (Indo-Aryan) loanwords, e.g. the numeral compounds aiga-, tera-, panza-, satta-, nāwa-wartanna ("one, three, five, seven, nine intervals",[11] virtually Vedic eka-, tri-, pañca- sapta-, nava-vartana. Kikkuli apparently was faced with some difficulty getting specific Mitannian concepts across in the Hittite language, for he frequently gives a term such as “Intervals” in his own language (somewhat similar to Vedic Sanskrit), and then states, “this means…” and explained it in Hittite" https://en.wikipedia.org/wiki/Kikkuli
This is consistent with the postulate of an Indo-Aryan superstrate in Mitanni. "Some theonyms, proper names and other terminology of the Mitanni are considered to form (part of) an Indo-Aryan superstrate, suggesting that an Indo-Aryan elite imposed itself over the Hurrian population in the course of the Indo-Aryan expansion....Sanskritic interpretations of Mitanni names render Artashumara (artaššumara) as Arta-smara "who thinks of Arta/Ṛta" (Mayrhofer II 780), Biridashva (biridašṷa, biriiašṷa) as Prītāśva "whose horse is dear" (Mayrhofer II 182), Priyamazda (priiamazda) as Priyamedha "whose wisdom is dear" (Mayrhofer II 189, II378), Citrarata as citraratha "whose chariot is shining" (Mayrhofer I 553), Indaruda/Endaruta as Indrota "helped by Indra" (Mayrhofer I 134), Shativaza (šattiṷaza) as Sātivāja "winning the race price" (Mayrhofer II 540, 696), Šubandhu as Subandhu 'having good relatives" (a name in Palestine, Mayrhofer II 209, 735), Tushratta (tṷišeratta, tušratta, etc.) as *tṷaišaratha, Vedic Tveṣaratha "whose chariot is vehement" (Mayrhofer I 686, I 736). Archaeologists have attested a striking parallel in the spread to Syria of a distinct pottery type associated with what they call the Kura-Araxes culture." https://en.wikipedia.org/wiki/Mitanni-Aryan