The other day there was a PBS show on Easter Island. The scientists were experimenting to see how the statues "walked" from the quarry to their final locations. Folklore said they walked, not were rolled or pulled.

The scientists make a statue of their own for experimentation. They explained the recipe for the "cement" that would make it the same density of the rock used in the statues. It was hypertuffa, though they didn't used those words.

And, yes, they did find a way to make the statue walk.