Originally Posted by Ursa major
The age of the stone is immaterial ...
Sorry, I was going back to the great pyramid there, not Japan.
Regarding the latter: these guys are begging for someone to study them properly. Scubaring around for a few minutes and then giving a verdict that can be interpreted 50/50 at best is not a proper investigation.
I accept that they could, just possibly, be natural formations -- in which case they would be a geological freak of nature and earn a special place in the geology books. You would have to study the foundations and surrounding bedrock to say anything conclusive about them, really?
There are very few straight lines and right angles in nature. They occur in crystals, of course, but seldom in rock formations -- like the Giants Causeway in Ireland.
On the other hand, they do look a lot like man-made structures ...