Taking that tooth, I trace two short white tracks
on the stone with it:
first, top to bottom;
then, left to right.
‘T’ denotes the spot.
I've been writing poems for each letter of the English alphabet. This is one of the shorter ones.
The letter 'T' is a descendent of the Semitic letter 'Taw', which looked like more like our 'X'. That letter in turn is thought to have derived from an Egyptian hieroglyph simply meaning 'mark'.
The poems are a sequence - you can read the first 19 on the links below: