The test in the article was extremely easy for me, I guess I can visualize better than most people (I had no idea some people have trouble with that). It's funny, because I've considered myself to be an "auditory" person.

Something I tried to visualize recently, and found quite challenging, was trying to remember this video: https://www.youtube.com/watch?v=9yW--eQaA2I

I watched it a couple of years ago, and last night I replayed it in my head, but with great difficulty.