Using sand and water to mold and shape hard stone?!🤯

I had the privilege of leading a group of Maori the indigenous people of New Zealand and they were all Maori School teachers that teach their own indigenous tradition in private schools. Through them are even on the trip. Every night I wasn't included they had to go into like a secret meeting but what they told me is right away. They looked at this. They said there's a way of doing this with sand and water that in their tradition they they're able to shape stone with sand. I have it remains to be seen but they have had they have some sort of method. They. They claim that this can easily be done with sand and water. I don't know for Christopher Dunn. We don't have the tools in the archaeological record to achieve this.