No doubt, however, it was a sun-dial, or gnomon of some kind.
The Gnomon is any one of the Diagonall with the two complements.
There is therefore in every Parallelogramme a double Gnomon; as in these two examples.
But I landed in the dark chamber of a Gnomon, waist-deep in loose wheat.
I mounted the only unsealed Gnomon and shouted down into its cavernous depths.