Scene of judgement from Egyptian "Book of the Dead" with heart glyph in left pan of scales, not at all like Indus DOWN HEART (Russmann 2001: 203).
Wells groups the instances with the longer left sides together with other horn-like signs that include more internal stripes, but considers the single instance that is reversed to be distinct (M-331). I am counting strokes and so group together those with four strokes, separating those with extra stripes. For my purposes, The "a" variant includes those with longer left side, as these are more numerous, and the "b" variant is the sole variant with a longer right side (and note that Wells again reverses these).
Fairservis defines the horn as meaning "horn; bull," even though he considers the sign to be that of a rhino or else a tusk. Luwian hieroglyphs seem to back him up, providing a similarly vertical CORNU, "horn" that even includes the internal horizontal stripe near the base. There is, in addition, a horizontal sign with a single straight side, the phonetic la.
Egyptian hieroglyphs include a bovine horn (F16). This is not vertically positioned and does not include a stripe. Roughly similar glyphs include a portion of the magical Wedjat eye of Horus, used as a fractional measure (D11), a fish scale (K6), and an ingot of metal (N34). The last is reasonably close in shape to an upside-down version of M-331, the "b" variant of the Indus sign. It lacks the horizontal stripe, though, as do all the potential Egyptian parallels.
Detail of painted hieroglyphs from a Theban tomb showing zigzag for "n" sound (Gardiner 1976: frontispiece).
Proto-cuneiform presents additional parallels. Interestingly, the closest semantic parallel lacks the internal stripe: SI came to mean "horn" as well as "ray, radiance, light." It looks somewhat like the Indus sign despite the missing stripe. Another with a similar shape that includes two stripes is SI4, which came to mean "red, brown." A triangle with its apex to the right that includes a single internal stripe appears very early to represent dairy fat (cream and/or butter), NI~b. A variant, NI~a, has a rounded, convex base. Proto-Elamite has the "b" variant except that it is reversed, with the apex to the left (M112~c), its meaning unknown.
The rock art of North America includes similar, horn-like motifs, although they lack internal striping. Two appear in the art of Texas, both oriented horizontally (Newcomb 1996: 43, Pl. 11, no. 2; 136, Pl. 91, no. 2). A single vertical occurrence appears in the corpus further west, which is more realistically bovine (Heizer and Baumhoff 1984: 194, fig. 131a).
Today's second Indus sign is shaped like a parenthesis or weakly curved "C," but delineated with doubled lines (IV32). I term it CEE for the "a" variant (18 occurrences) and BACK CEE for the reversed "b" variant (one occurence). A third variant is pointed on the ends, much like a crescent, the "c" variant (two occurrences). One instance is squared off at the top end, but rounded and fatter at the bottom. If we wish to be very precise, we may denote this a "d" variant (M-407).
This sign was previously known as KP175, W573, Fs H-9. Fairservis considers it a shield, possibly a variant of the simpler CEE (his H-3). It seems possible it was intended to represent the moon, as with the Egyptian N11, a horizontal crescent moon. But note that Luwian hieroglyphs include two backward "C" shapes close together to indicate VIA, "road."
A very close parallel is presented by proto-cuneiform RU, a backward "fat cee," which came to mean "present, gift, offering" and the related verb "to give, offer, send." There is a similar but more angular proto-Elamite sign as well (M343). Old Chinese has a character that is something like a more deeply curve "C" also. It appears both in the simple form, a single line, and in the "fat" form of doubled lines, with internal striping. This is fang1, "the primitive wooden vessel, a log hollowed out....By extension, chest, trunk, box" (Wieger 1965: 141). This is now the 22nd radical.
A coil on a post used in Sumer to represent the goddess Inanna (original artwork based on a cylinder seal).
In Old Europe, a similar shape appears only in the upside-down "U" shape (or ROOF in my terms). This is motif DS166. Similarly, in the rock art of Australia, I find a motif of a very open curve only in the ROOF configuration in an Olary petroglyph from Panaramitee North (Flood 1997: 129).
Another ZIGZAG is next, this one in the likeness of our letter "W" (IV33). I named it DOWN EM since I had previously used DUBYA for another Indus sign. This is also KP190 and W434, not shown in Fairservis. Egyptian hieroglyphs include the very common phonetic glyph for the sound of "n," representing water. This has more humps that the "W" though. Proto-cuneiform has an identical sign in BIR3~b, "yoke; team (animal)." Proto-Elamite also duplicates the sign (M051~c). The same shape also appears in the Old European motif corpus (OE 90) and in runes for "s" (FUTHARK). There appear to be only two instances of this particular form of the ZIGZAG in the Indus corpus (H-461 and K-113). A long zigzag occurs on a pot shard from Rangpur (Rgp-2) with four humps.
The thirty-fourth sign is DOWN HEART (IV34), also known as KP196, W256, and Fs E-6b (i.e., I presume he would interpret this as a stemless version of the LEAF, E-6a). There are three occurrences of this sign, according to Wells, two at Mohenjo daro (a fat one, M-407, and a thin one, M-331F), and one at Harappa (a thin one, H-42). I see a doubled set on one more, M-1316, where they are smaller than neighboring signs.
There are not as many parallels from other symbol systems as for many other Indus signs. There are no heart shapes among the Egyptian or Luwian hieroglyphs, for example. Egyptian does include a heart, but it actually is a drawing of a heart, with truncated parts where the arteries have been sliced short. Similarly, in Old Chinese, the character xin1 represents the heart (Wieger 1965: 258). But unlike a Valentine style heart, it follows the contour of the actual heart, with three lobes at the bottom.
Proto-cuneiform does have a sign something like this, although it is more angular and upside-down or rotated 90 degrees, depending on the variant. This is DIN, which came to mean a number of things, including "wine," perhaps the original significance.
The rock art of North America includes a similar motif only rarely. I see one such instance in Texas (Newcomb 1996: 153, Pl. 105, no. 7). There are at least three occurrences in the corpus from further west, two of them upside-down compared to the Indus symbol (Heizer and Baumhoff 1984: 131, fig. 68a; 142, fig. 79b; 161, fig. 98m). Only the last is in the same orientation as IV34.
The final sign considered here is COIL WITH TICK, IV35, formerly KP343, W77, not shown in Fairservis. It is a singleton, appearing only at Lothal (L-26). On that one seal it occurs in initial position, shorter than other signs as it compensates for its position over the horn of the unicorn bull that is the icon.
Proto-cuneiform contains coiling signs in the ZATU697 set, among them the "a" variant being closest to the Indus COIL in appearance. But there is nothing comparable to the "tick" added to the ancient Iraqi coils. In addition, the Sumerians of a somewhat later time used a coiled reed on a post to symbolize a goddess, Inanna. If we consider the coil itself to be equivalent to the Indus COIL, then the post could be thought of as equivalent to the "tick." This symbol for Inanna survived for a long time, appearing on boundary stones called kudurru into the Kassite period of Babylonian supremacy, when the same symbol represented Ishtar. Inanna/Ishtar was, by that time, the goddess of erotic love, but also of war, associated with the planet Venus as morning star and evening star.
Among the Old European motifs, there are two elements similar to our small "y," in which the lower stem is carried out into a coil. If we flip this coiling "y" upside down, this makes the element OE214a, in which we might imagine the shorter leg to be the "tick." If, instead, we flip the "y" in reverse and add serifs on top, this is a fair description of the "b" version. In this, again, we might imagine the shorter leg of the "y" to parallel the "tick" of the Indus sign.
In the rock art of Nevada and eastern California, there are a good many spirals and coils. In one instance, a coil appears with five ticks added to its lower bend (Heizer and Baumhoff 1984: 169, fig. 106). This unusual motif occurs above a more usual spiral with three coils.
Russmann, Edna, ed. 2001. Eternal Egypt: Masterworks of Ancient Art from the British Museum. Berkeley: University of California Press & American Federation of Arts.
Black, Jeremy and Anthony Green. 1992. Gods, Demons and Symbols of Ancient Mesopotamia: An Illustrated Dictionary. Austin: University of Texas Press. (info on kudurru symbols)