It’s a magic trick for the eyes. I want you to watch it and see if you:
a) Believe it’s real and can be done
b) Think it’s the pencil
c) Think it’s the positioning of the nuts
d) Think something else is going on

At 20 seconds, stop the video and ask yourself, how is this happening? Don’t be vague like, ‘it’s the pencil’, or ‘there’s something up,’ try to guess specifically what is going on.