https://techcrunch.com/2018/06/08/zoetrope-effect-could-render-hyperloop-tubes-transparent-to-riders/

An optical illusion popular in the 19th century could make trips on the Hyperloop appear to take place in a transparent tube. Regularly spaced, narrow windows wouldn’t offer much of a view individually, but if dozens of them pass by every second an effect would be created like that of a zoetrope, allowing passengers to effectively see right through the walls.

It’s an official concept from Virgin Hyperloop One and design house Bjarke Ingels Group (BIG), and in fact was teased back in 2016. Now the companies have shared a video showing how it would work and what it would look like for passengers — though there’s no indication it would actually be put in place in the first tracks.