"My apartment builder fixed this random looking thing on the roof .Not sure what it is and what it does. It was recently fixed and I’m not sure if it is anything significant. Can anyone fill in my curiosity."
A: "It’s a reflector for surveying. Most likely used to determine building movement/settling over time."
See? That wasn't hard.
Let me jump in here with a layman's explanation, It's a Keychains that has an articulated bear attachment, I'll be back next week with more facts for your delectation.