How formation of day and night suggest the rectilinear propagation of light?

The formation of day and night suggests the rectilinear propagation of light because when the Earth rotates on its axis, the sunlight falls on one side of the Earth creating day, while the other side facing away from the Sun is in darkness, creating night. This implies that light travels in straight lines from the Sun to the Earth, illuminating only the side facing the Sun at any given time.