My thoughts are, that some of the symbols you found are possibly territory markers from early tribes who inhabited the region. I also thought the Pashupati Seal exhibited similarities to the markers you found.
History of Pakistan
Situated on the first coastal migration route of Homo sapiens out of Africa, the region was inhabited early by modern humans. The 9,000-year history of village life in South Asia traces back to the Neolithic (7000–4300 BCE) site of Mehrgarh in Pakistan and the 5,000-year history of urban life in South Asia to the various sites of the Indus Valley Civilization, including Mohenjo Daro and Harappa.
The Pashupati seal (also Mahayogi seal, Proto-Śiva seal; the adjective "so-called" sometimes applied to "Pashupati"), is a steatite seal which was uncovered in the 1928–29 Archaeological Survey of India excavations of the Indus Valley civilisation ("IVC") site of Mohenjo-daro, then in the British Raj, and now in Pakistan. The seal depicts a seated figure that is possibly tricephalic (having three heads). The seated figure has been thought to be ithyphallic (having an erect penis), an interpretation that has been questioned by many. The man has a horned headdress and is surrounded by animals. He may represent a horned deity. It has one of the more complicated designs in the thousands of seals found from the Indus Valley civilization and is unusual in having a human figure as the main and largest element; in most seals this is an animal.