The difference between these pictures is the angle of lighting used when the photo was taken.  Possibly difficult to see at this size; wider larger images are available via the links below.

There is a "stacked" glyph centrally located in the pics.  And some smaller glyphs surrounding. 

These engravings bear a number of striking similarities with Central and South American burial art, and stele. 

Larger left side image
Larger right side image