Danielle, I thought that too and I'm very familiar with the Escher angle illusions - but with Shirley here, that guy is famous for his video edit magic and if you look at the last frames and freeze it, it's had an edit. If the final cube was placed correctly, you would still see the red side from the camera angle in front of the rear blue/yellow surfaces.

Very well made and clever though

Lucas,
...and the bathroom sink drain.