Imagine again that you have a mirror.
If you use the mirror to ‘shine’ sunlight into he smoke column you would see?
A square. You have seen the displays that project an image onto a water vapor - yes?
If the smoke column has a white object in ‘front’ of it, with square corners or straight lines, the light would reflect sunlight onto the smoke column. And the light would appear to be a straight line in the smoke.
Or not.
I could imagine I had a warp drive. Flew into the future. Retrieved some lingering souls who had nothing to do at the moment. Bring them back (to drink the going brew of the time period for ‘scientific purposes’ of course) With all of their equipment and receive a big WTF.