These crude tools were around for thousands of centuries, until around 1.4 million years ago when Homo erectus started shaping single, thin stone blades, sometimes rounded ovals, but often in what are to our eyes an arresting, symmetrical pointed leaf or teardrop form.
Need rohmakad tööriistad olid olemas tuhandeid sajandeid kuni umbes 1,4 miljonit aastat tagasi hakkas Homo erectus neid tahuma õhukesteks kiviplaatideks, mis vahel olid ovaalsed, kuid enamasti meenutasid sümmeetrilist teravatipulist lehte või pisarat.