A rooftop terrace on the National Museum of Scotland  in Edinburgh, holds a series of four sculptures made of massive sandstone blocks.
The work is Hutton Roof, Split and carved sandstone by Andy Goldsworthy, 1998. The words on the explanatory panel tell the story.
“The four sandstone sculptures behind you, placed as the four points of the compass, evoke the theories of the pioneering Edinburgh geologist James Hutton. The sandstone, from Locharbriggs quarry, Dumfriesshire, is the now compacted sands of a 270 million-year-old desert.
Each stone has been split along its natural grain into five slices, with a hole carved into each slice. When each stone is reconstructed, the holes align to draw the eye of the viewer down into the centre, subliminally back through the layers of time.”
The photographs in the panel above show the Hutton Roof description, two of the blocks and three views from above the blocks down through ‘time’. The one at the top of the page was taken across the top of one block, in slanting sunlight to show the surfaces.
 National Museum of Scotland, Chambers St, Edinburgh www.nms.ac.uk.
 James Hutton (1726-1797) geologist and farmer after whom the James Hutton Institute is named (https://www.hutton.ac.uk). For information on James Hutton, see Encyclopaedia Britannica and Wikipedia.
Author / contact: email@example.com. Visit to Hutton Roof, 27 August 2013.