Cities around the world are populated with grand television towers, but Toronto has one with a twist: the colored patterns of LEDs along its shaft are very often thin-sliced imagery. It’s a convergence of lighting and motion imagery that’s too get to pass up on this site. The Torontoist blog turns to visual effects designer / compositor Avi Salem to “decode” that imagery. He tells them in an email:

Since [each image pans] across the elevator shaft revealing a sliver of itself, all I had to do was do the opposite. Using compositing software, I created a slit scan effect on the elevator shaft, and then overlaid it on the original footage.

In detail: I cut out the shaft from the footage and moved it across the screen over time at the same speed the image is scrolling. On top of this I applied an effect that will leave a trail of the shaft as it moved along. This left me with a long image. Finally, I moved the image in reversed, created a reveal in front of the tower, and overlaid it over the original footage.

CN Tower’s Flashing Images, Unfolding Like a Film Strip

They also point to a slit-scan iPhone app, for fun.

Okay, Berliner Fernsehturm, time to up your game.