Svastika in Sarasvati civilization:
Indian Numismatics by D.D. Kosambi, ICHR 1991 (Contains a detailed review of devices shown on early punch-marked coins; many devices are comparable to Sarasvati hieroglyphs. A remarkable evocation of the metallurgical tradition of mints producing coinage.)
Sarasvati Epigraph corpus (Indus Script corpus) (289mb pdf file for download only)
Parallels in Ancient Near East -Sarasvati glyphs: bronze age metals trade 16mb free http download
Four 'rosetta stones' to decode Sarasvati hieroglyphs as mleccha writing:
Meluhha merchant/smith (Akkadian cylinder seal)
Two Tin ingots discovered at Haifa (with Sarasvati hieroglyphs)
tabernaemontana glyph in front of zebu bull (mleccha: tagaraka, 'flower', 'hair fragrance', 'tin' (Ur cylinder seal)
Four 'rosetta stones' validate
Why are these 'rosetta stones'?
Bronze age trade and writing system are related inventions.
Necessity was the mother of these inventions.