The "play doh theory" for lack of a  better term to describe it is an ancient technique used in building and construction made  by the first civilisations of mankind prior to the Flood, It was lost to time. AI  search assist will sufficiently inform as to what it is but never How it was accomplished - of cause. That then leaves more of the topic over to us to find out, So basically what we know after diving down very, very long distant rabbit holes is that the ancient peoples wiped out by the biblical Flood knew about geo polymers which must also mean they had provisions to make the polymer or it was a natural product made by natural or both and that is what it was. ~ Children's play doh can be made with 3 simple ingredients as we know with cornflour - baking soda - water, with an optional addition of food colouring for a brighter out come leaving kids with hours of creative play. Well it was the same 'technique' used by the ancient ones to Create their gigantic stone walls and what today we call monuments of the forgotten past. With just three simple ingredients it seems they built their entire world. They Made The Stones ! - from pulverised rock - water glass - and water.  They created each individual rock shape in real time as they progressed in their construction,  We can see how Flexible molds ( possibly made from leather ) were positioned according to the shape required to be filled. The tell tale sign is the mistakes in the process that they left behind for us to see to this very day and it is these that prove the play doh theory point. The protrusions we see at the base of some 'rocks' come from drainage points where the molding bag had be pierced to release excess water which was meant to evaporate. ( They were not looking for utter perfection it seems )