Modern scientific improvements also enable us to enter into stone, because they provide for excavating so many subways, penetrating the hills, etc. So , the mystic perfection of trying to enter into stone, has also been achieved by material science: Revision history
Diff selection: Mark the radio buttons of the revisions to compare and hit enter or the button at the bottom.
Legend: (cur) = difference with latest revision, (prev) = difference with preceding revision, m = minor edit.