The Knot thing is a two person juggling routine that even beginners can master during their first lesson.
It is simple, start-/stoppable at any point etc. You could think it’s almost nothing, but it is the Knot Thing!
One “difficulty” might be making it look good, by keeping a steady rhythm and using a grand gesture for the knot handover, as mentioned above.
PS: Next up: The Sandiplex-5
Side note: I was repeatedly asked whether the drawings were anatomically correct. My answer is always the same: Yes.