It turns out that the seemingly random lights flashing on the CN Tower in Toronto, Canada are actually images! Behind the elevators are some powerful lights that appear to be flashing randomly. The way they achieve this ‘randomness’ is by ‘printing’ images line by line, sort of like a huge inkjet printer.
YouTube user avi has used some fancy photography to recreate what those images look like. You might notice some thin black lines criss-crossing the image, that is the elevators blocking the lights as they go up and down. Have a look at the video below.