I was trying to make an impossible hallway using command blocks and relative teleporting.
I expected to be teleported smoothly so I wouldn't notice that I teleported.
What actually happened was that the screen flickered as if it was an earlier update
This video made by Jesper The End will explain what I was trying to recreate.
https://www.youtube.com/watch?v=469wMsx3FXw&list=UU9kL6xKKDIQN3CtrJRL4JmQ
Thanks for your time.
Duplicate of MC-4686