Sacsayhuaman is an Inca walled complex near the old city of Cusco, at an altitude of 3,701 m.
Some believe the walls were a form of fortification, while others believe it was only used to form the head of the Puma that Sacsayhuaman along with Cuzco form when seen from above. Like much Inca stonework, there is still mystery surrounding how they were constructed. Source
Engraving is the practice of incising a design onto a hard, usually flat surface by cutting grooves into it.
The effects of line engraving are produced by lines of different width and closeness, cut with the burin upon copper or similar material.