Not sure what that man is doing there, as the scale is way off (and inconsistent).
One of the ways they worked granite (and surely more applicable to the case) was bashing it with dolerite pounders. Not sure why anyone would attempt it in the way you’ve described.
So, well done. You’ve given us an argument for the blocks not existing: a brilliant job of non-explaining them. This is what tends to happen, when your object and method is naysaying.