![Matt Parker on Twitter: "For people asking: the Klein Bottle Hat I'm wearing requires some self assembly. Here is the knitting pattern: https://t.co/D6I1IF4Ez8 https://t.co/uHDeBHbaUF" / Twitter Matt Parker on Twitter: "For people asking: the Klein Bottle Hat I'm wearing requires some self assembly. Here is the knitting pattern: https://t.co/D6I1IF4Ez8 https://t.co/uHDeBHbaUF" / Twitter](https://pbs.twimg.com/media/DiIztcvXkAAbpYj.jpg)
Matt Parker on Twitter: "For people asking: the Klein Bottle Hat I'm wearing requires some self assembly. Here is the knitting pattern: https://t.co/D6I1IF4Ez8 https://t.co/uHDeBHbaUF" / Twitter
![Matt Parker on Twitter: "Hey everybody, remember how much you like Klein bottles? Get in there and vote for them now! https://t.co/vIpolJgvcz https://t.co/1eQdaRDCXP" / Twitter Matt Parker on Twitter: "Hey everybody, remember how much you like Klein bottles? Get in there and vote for them now! https://t.co/vIpolJgvcz https://t.co/1eQdaRDCXP" / Twitter](https://pbs.twimg.com/media/DiIcnBFXUAAw9Ie.jpg)
Matt Parker on Twitter: "Hey everybody, remember how much you like Klein bottles? Get in there and vote for them now! https://t.co/vIpolJgvcz https://t.co/1eQdaRDCXP" / Twitter
![Free Knitting Pattern for Klein Bottle Hat | Easy sweater knitting patterns, Hat knitting patterns, Knitting patterns Free Knitting Pattern for Klein Bottle Hat | Easy sweater knitting patterns, Hat knitting patterns, Knitting patterns](https://i.pinimg.com/236x/22/b5/f7/22b5f73bf550ab5a62229b8aca3c3c12.jpg)