Final answer:
Objects displayed above ground level, such as artistic installations and ancient geoglyphs, serve to indicate obstacles or boundaries, often carrying symbolic meanings that interact with the landscape and influence human perception.
Step-by-step explanation:
The question pertains to objects displayed above ground level which serve the purpose of indicating an obstacle or delineating a boundary. These objects can be found in various contexts and are often construed from natural materials such as stone, or in modern installations, from materials like stainless steel, which can be seen in the artwork called Reverse City. They can take on symbolic meanings, like the massive colored pencils in Reverse City, where each pencil is a different length and etched with the names of countries, creating a global village. Furthermore, objects like geoglyphs, such as the Nasca lines with their immense zoomorphic designs, also depict this concept, with images like the hummingbird stretching over 300 feet in length. In both cases, there is an interaction with the landscape, where features like proximity (near, above, below), direction (to the left, to the right) and distance (in the distance, in the foreground, in the background) contribute to the overall perception and interpretation of the objects and their intended symbolisms. These installations and ancient drawings illustrate how humans have manipulated landscapes to communicate messages, mark territories, and create art that interacts with viewers' perception, often prompting them to read the landscape in a more attentive way as suggested by the notion of Jedi Goggles.