As these shapes pre-date the arrival of Latin in Britain, if we want to look at any alphabets, we need to look at Greek or Phoenician.
We're told here
that the Greek alphabet was based on the Phoenician alphabet
The Greek letter Tau
was based on the Phoenician letter Taw (X). Apparently X means a mark. Or X marks the spot?
I think TME has already had posts on the Celtic Cross as a boundary marker and/or navigation tool.
At this point, I have a few problems.
If we take it literally, Tau sounds very like Tor, and many of these hill tops (in Devon and Cornwall) are called Tors. Dartmoor especially is covered in them, which could get me excited. But would I be confusing the pattern with the parts of the pattern?
There are no Tor hilltops in Dorset, because a Tor is just supposed to be a hill with naturally occurring rocks on the top. But what does a Tor get called after humans have taken all the rocks and rearranged them in a ring on top of the hill to make an enclosure?
I'm not sure why Glastonbury Tor is called a Tor.