This mechanism shrinks when pulled

How an unlikely physics paradox controls these counterintuitive structures. Sponsored by Incogni - Use code veritasium at https://incogni.com/veritasium to get an exclusive 60% off.

If you’re looking for a molecular modeling kit, try Snatoms, a kit I invented where the atoms snap together magnetically - https://ve42.co/SnatomsV

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A huge thank you to Paul Ducarme and Bas Overvelde at AMOLF for showing us around.
Check out their research on counter-snapping structures here - https://ve42.co/CounterSnapping

For more on Braess’s Paradox, check out these great videos by Up and Atom (   • Braess's Paradox - Equilibria Gone Wild  ) and Steve Mould (   • The Spring Paradox  )

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0:00 What happens if you cut this rope?
1:41 The Spring Paradox
4:59 New York’s Perplexing Discovery
6:29 Road Networks and Traffic Flow
8:40 Braess’s Paradox
14:29 Snapping
17:16 This object shrinks when you stretch it

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References:

Ducarme, P., Weber, B., Hecke, M. van, & Johannes. (2025). Exotic mechanical properties enabled by countersnapping instabilities. Proceedings of the National Academy of Sciences - https://ve42.co/CounterSnapping
Braess's Paradox via Wikipedia - https://ve42.co/BraessWiki
Braess, D., Nagurney, A., & Wakolbinger, T. (2005). On a Paradox of Traffic Planning. Transportation Science - https://ve42.co/Braess2005
Schäfer, B., Pesch, T., Manik, D., Gollenstede, J., Lin, G., Beck, H.-P., … Timme, M. (2022). Understanding Braess’ Paradox in power grids. Nature Communications - https://ve42.co/Schafer2022
Kolata, G. (1990). What if They Closed 42d Street and Nobody Noticed? New York Times - https://ve42.co/Kolata1990
Youn, H., Gastner, M. T., & Jeong, H. (2008). Price of Anarchy in Transportation Networks: Efficiency and Optimality Control. Physical Review Letters - https://ve42.co/Youn2008
Nicolaou, Z. G., & Motter, A. E. (2012). Mechanical metamaterials with negative compressibility transitions. Nature Materials - https://ve42.co/Nicolaou2012
Counter-Snapping replication package - https://ve42.co/CSPackage

Images & Video:

Earth Day Festivities via VHS Music Rarities -    • B 52s - Channel Z (Live Earthday 4/22/1990...  
Earth Day Speeches -    • Earth Day 1990 - Central Park, NY  
1990s New York via NYC Nostalgia -    • NOSTALGIA: Life in 1990s New York Was Amaz...  
42nd Street Closure via Trainluvr -    • Transit Day 1990  Auto-Free 42nd St  
42nd Street Traffic Operator - https://ve42.co/NYCTraffic
Dietrich Braess via opc.mfo.de - https://ve42.co/BraessOPC
Dietrich Braess via Wikipedia - https://ve42.co/BraessWikiPic
Belt Buckle via Mingda Hardware - https://ve42.co/BeltBuckle

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Special thanks to our Patreon supporters:
Adam Foreman, Albert Wenger, Alex Porter, Alexander Tamas, Anton Ragin, armedtoe, Balkrishna Heroor, Bertrand Serlet, Blake Byers, Bruce, Charles Ian Norman Venn, Dave Kircher, David Johnston, David Tseng, Evgeny Skvortsov, Garrett Mueller, Gnare, gpoly, Jeromy Johnson, Jon Jamison, JT, Juan Benet, Keith England, KeyWestr, Kyi, Lee Redden, Marinus Kuivenhoven, Matthias Wrobel, Meekay, meg noah, Michael Krugman, Orlando Bassotto, Paul Peijzel, Richard Sundvall, Robert Oliveira, Sam Lutfi, Tj Steyn, TTST, Ubiquity Ventures, and wolfee

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Writers: Gregor Čavlović & Derek Muller
Producer & Director: Gregor Čavlović
Editors: James Stuart & Trenton Oliver
Camera Operators: Sander Mook, Dylan Meanwell, Fabio Albertelli, Casper Mebius & Gregor Čavlović
Animator: Fabio Albertelli
Illustrator: Jakub Misiek
Additional Editor: Peter Nelson & James Horsley
Researchers: Darius Garewal & Gabe Strong
Thumbnail Designers: Ren Hurley & Ben Powell
Production Team: Rob Beasley Spence, Tori Brittain & Matthew Cavanagh
Executive Producers: Derek Muller & Casper Mebius

Additional video/photos supplied by Getty Images, Pond5.
Music from Epidemic Sound