Obelisk Sketch

"For the non-interactive drawings of the Obelisk found all over the peninsula, please see Obelisk Drawing."The Obelisk Sketch is a collectible story item that can be found in Cave 10. It can be seen in the Sahara research lab, but it can only be interacted with in Cave 10. Upon discovery, it will be examined and then added to the notes section of the survival guide.

Theory
It appears to be a fancy, modern drawing of the resurrection obelisk. There appear to be numbers and a formula on the bar measuring the top spire of the obelisk. Because this item can be found both in the lab and in cave 10, two assumptions can be made. First, the sketch belongs to a Sahara employee, along with the orange, modern tents nearby. Second, and alternatively, the cannibals that overran the lab could have dropped this randomly in the camp in Cave 10, as they often drop items off in the caves.