Uploaded September 2019 | Updated September 2026, 2 weeks ago

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Check out Geoff's video from the same day!
youtu.be/IIMbF_Amuc4
Thanks very much to Vicki and Geoff for all their help.

If you want some more maths, and the 'rules' for finding a Tube Knot, check out the bonus content video on my second channel.
youtube.com/watch?v=Qp2LDpJo-Ng

Henry and Sabetta also went and double-checked all of the overs and under in our knot.
youtube.com/watch?v=nJuODe8aVm0

Huge thanks to Sabetta and Henry. Here is the first video I made with them: Exploring Hyperbolic Space with VR
youtube.com/watch?v=MTfviv_aZYI
And my spherical camera video with Henry.
youtube.com/watch?v=x0gRcRd_rHs

Here is everyone's channel:
Vicki Pipe: youtube.com/user/VickiPipe
Geoff Marshall: youtube.com/user/geofftech2
All the Stations: youtube.com/channel/UC7ttKX46nJxUeXZ0aoD4Q5g
Henry Segerman: youtube.com/user/henryseg

Worksheet and teaching resources to find your own underground knots!
think-maths.co.uk/standupmaths-videos?yt-tube#tube

Here are the detailed "Carto Metro" maps you can use to check which line goes under/over which.
http://carto.metro.free.fr/metro-tram-london/


CORRECTIONS
- At 13:19 I call Green Park "West Park" when talking about going west. First noticed by Geoff Marshall, of course.
- Let me know if you or Geoff spot anything else!


Thanks as always for Jane Street being my principal sponsor.
janestreet.com

Thanks to my Patreon supporters who help make these videos possible. Here is a random subset:

Deanv Crouch
Brandon Bisel
Claire Greenhalgh
Vojtěch Mělnický
Gary Martin
Nelson Emerson

Support my channel and I can make more maths videos:
patreon.com/standupmaths

Filming by Matt Parker and Geoff Marshall
Editing by Michelle Martin
Music by Howard Carter
Design by Simon Wright

MATT PARKER: Stand-up Mathematician
Website: standupmaths.com
Maths book: wwwh.umble-pi.com
Nerdy maths toys: mathsgear.co.uk