Brewers Dictionary of Phrase and Fable steers us back to Latin in explaining that Pliny thought hyenas had a kind of stone in their eye, that if you put under your tongue gave the gift of prophecy.
They made joints in stone keeping the lintels in place horizontally using a tongue and groove joint and subsequently fixing the upright and lintel with a ball and socket joint or mortice and tenon.
The paper presents a successful numerical simulation of the stonetongue formation in blasting toe-shooting by distinct element method, and an analysis of the numerical simulation results.