I worked out why some people were having trouble rotating their wedge. Take a look at the wedge in video 19, then take a look at the wedge in video 20. You might notice the wedge is pointing down the X axis in vid 19 and suddenly it’s pointing down the Y axis in vid 20…
I’m guessing he needed to re-make his wedge between videos for whatever reason and accidently made the new wedge differently, So if you’re struggling with the rotation challenge this is probably why.
If you had your wedge pointing down the X axis like in video 19 you might find that in order to get your wedge pointing upward you’ll need to rotate it -90 degrees on the Y axis. In the pic above the wedge pointing down was rotated +90 degrees and ended up pointing down. I re-made the other wedge to point down the Y axis like how it was in video 20 and had no problem with the challenge after that.