Common English would perhaps go with “spent.” But the guys who made this are Thai, at least that is what is said in the description.

Sort of wild, not sure what to believe about some of it, but it is a kick to watch.

No idea about the medium they are digging in. I’ve read of some types of stone that are relatively easy to carve. But that stuff looks like it’s too easy to carve and retain that shape and support weight as well.

I know that underneath topsoil in many places is a layer referred to as “hardpan.“ It’s a serious PITA To dig in, I’ve never gotten very far into it, never had any desire or need to do so.

The final result does look sort of nifty, the hard part would be keeping that water from stinking like hell.

https://youtu.be/d6QXxMDp7Zg