- Math-Life balance, a videochannel run by Mura Yakerson.
- MathOverflow, a stackexchange page for professional mathematics
- Original soundtrack of David Hilbert speaking about "Naturerkennen und Logik" (in german)
- With this shocking application of the fundamental group it is demonstrated that clipping two carabinders together can have an unexpected effect.
- Here one can play games like chess or tic-tac-toe on closed surfaces like the Klein bottle.
- It is shown how to slice a bagel into two linked halves.