The first 100 people to use code SCIENCE at the link below will get 60% off of Incogni: https://incogni.com/science

Steffen's polyhedron is a flexible concave polyhedron. Euler thought such a shape was impossible. I also show infinitesimally flexible polyhedrons and bistable polyhedrons.

Here's Ivan's channel:    / @ivanmirandawastaken  

Here's my Discord server:   / discord  

Additional filming by Nicole Jacobus

You can buy my books here:
https://stevemould.com/books

You can support me on Patreon and get access to the exclusive Discord:
  / stevemould  

just like these amazing people:

Tj Steyn
Pavel Dubov
Lizzy and Jack
Jeremy Cole
Brendan Williams
Alan Wilderland
Frank Hereford
Lukas Biewald
Damien Szerszinski
Heather Liu
Grant Hay
John Zelinka
Paul Warelis
Matthew Cocke
Nathan Blubaugh

Twitter:   / moulds  
Instagram:   / stevemouldscience  
Facebook:   / stevemouldscience  
Buy nerdy maths things: http://mathsgear.co.uk