Rebecca, of course that type of categorisation is possible when you have a large sample to work with, which is the case for the examples you quote. But it is still not properly scientific - it is subjective. So an archaeologists looking at stone tool is making a subjective evaluation of its shape and therefore its likely origin. I agree, this is accepted as being 'good enough' in many areas of science where there is a sufficient database of examples. However, these kinds of observation are often controversial - we see these kinds of argument in the research literature all the time - and they occur precisely because of the inherent subjectivity and limited datasets. You then suggest the same 'categorisation' can be made for this single symbol when we have an extremely limited dataset. You will not be able to convince anyone this is scientific. You are preaching pseudoscience, trying to dress it up as rigorous because it agrees with your opinion.