Proto-writing  Proto-writing consists of visible marks communicating limited information. Such systems emerged from earlier traditions of symbol systems in the early Neolithic, as early as the 7th millennium BC. They used ideographic or early mnemonic symbols or both to represent a limited number of concepts, in contrast to true writing systems, which record the language of the writer. In 2003, tortoise shells were found in 24 Neolithic graves excavated at Jiahu, Henan province, northern China, with radiocarbon dates from the 7th millennium BC. According to some archaeologists, the symbols carved on the shells had similarities to the late 2nd millennium BC oracle bone script. Others have dismissed this claim as insufficiently substantiated, claiming that simple geometric designs such as those found on the Jiahu shells cannot be linked to early writing. The Vinča symbols (6th to 5th millennia BC, present-day Serbia) are an evolution of simple symbols beginning in the 7th millennium BC, gradually increasing in complexity throughout the 6th millennium and culminating in the Tărtăria tablets of c. 5300 BC. The hieroglyphic scripts of the Ancient Near East (Egyptian, Sumerian proto-Cuneiform and Cretan) seamlessly emerge from such symbol systems, so that it is difficult to say at what point precisely writing emerges from proto-writing. Adding to this difficulty is the fact that very little is known about the symbols' meanings. The transition from proto-writing to the earliest fully developed writing systems took place in the late 4th to early 3rd millennia BC in the Fertile Crescent. The Kish tablet, dated to 3500 BC, reflects the stage of "proto-cuneiform", when what would become the cuneiform script of Sumer was still in the proto-writing stage. By the end of the 4th millennium BC, this symbol system had evolved into a method of keeping accounts, using a round-shaped stylus impressed into soft clay at different angles for recording numbers. This was gradually augmented with pictographic writing using a sharp stylus to indicate what was being counted. The transitional stage to a writing system proper takes place in the Jemdet Nasr period (31st to 30th centuries BC). A similar development took place in the genesis of the Egyptian hieroglyphs. Various scholars believe that Egyptian hieroglyphs "came into existence a little after Sumerian script, and ... probably [were] ... invented under the influence of the latter ...", although it is pointed out and held that "the evidence for such direct influence remains flimsy" and that "a very credible argument can also be made for the independent development of writing in Egypt ..."