In this talk, we will present our recent work on the behavior of geodesic trajectories on convex flat cone spheres. This research is partly motivated by the study of billiard paths in convex polygonal billiards. Specifically, we establish that the length of a geodesic can be approximated by the square root of its self-intersection number, in a uniform sense. Additionally, we demonstrate that in families of flat cone spheres with poles, the behavior of the geodesic flow is trivial in the sense that there are no closed orbits.