The closed path is a geodesic triangle: each edge is a great-circle arc on the unit sphere. The arrow is
parallel-transported along that path — it stays tangent, with no twisting off the surface, so the local
geometry (the Levi–Civita connection) decides how it turns at each step. When the loop closes, the arrow
generally points somewhere new relative to its start; the deficit angle at lower right is that rotation,
i.e. the holonomy. On a unit sphere it equals the area enclosed by the loop. Drag the view to orbit the
scene.