whenever she studied a worn , broken piece of stone , puzzling over the figures so roughly etched into the surface and almost worn away by time and the elements , she always wondered about the writers : who had they been , what had they been thinking that was important enough for them to crouch for hours over a bit of stone , legs cramping , back and arms aching , as they cut the images into the stone with little more than the sharpened edge of another piece of stone ?