What directions does light travel?

Probably the simplest answer is that light travels in all directions. That does need some clarification, though, so let's start with how light is produced. Light is produced when a charged particle vibrates. That electrical vibration induces a magnetic one. Those paired vibrations then propagate outward from the source, as "a series of concentric spheres spaced in accordance with the vibration of the source." Imagine a pebble being dropped into a still pond. The waves move outward in concentric spheres. With that said, light will reach a destination; therefore, a line can be drawn, perpendicular to the wave fronts, that runs from the source to the destination. This in turn causes people to say that light travels in a straight line. Those lines are called rays. If you are only examining a hypothetical single ray, then it is not possible to say that light travels in all directions. Things can be complicated even more once you introduce refraction, reflection, and diffraction. A reflected light wave will change directions. The other two interactions will cause light to bend in a new direction.
http://www.pas.rochester.edu/~blackman/ast104/ref-diff.html

https://sciencing.com/light-travel-4570255.html