The student exchanges a black cartridge.
text: You'll have to push it in a bit more horizontally, so rotate it a bit towards the back.
text: You can pull it out and maybe turn it ninety degrees.
text: Uh, the other way.
text: Ninety degrees away from you.
text: So you can rotate it back to how it was and then now ninety degrees away from you, the other ninety degrees.
text: Perfect.
text: And then it goes in that direction.