![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
![Schoolhouse Press - Two Klein Bottle Hats - SPP53 - Schoolhouse Press Patterns - Patterns | Klein bottle, Knitting, Diy sewing Schoolhouse Press - Two Klein Bottle Hats - SPP53 - Schoolhouse Press Patterns - Patterns | Klein bottle, Knitting, Diy sewing](https://i.pinimg.com/originals/a5/ec/3f/a5ec3f7b3100bc31539dac851a321d26.jpg)
Schoolhouse Press - Two Klein Bottle Hats - SPP53 - Schoolhouse Press Patterns - Patterns | Klein bottle, Knitting, Diy sewing
![Free Knitting Pattern for Klein Bottle Hat | Hat knitting patterns, Knitting patterns free hats, Beanie knitting patterns free Free Knitting Pattern for Klein Bottle Hat | Hat knitting patterns, Knitting patterns free hats, Beanie knitting patterns free](https://i.pinimg.com/736x/22/b5/f7/22b5f73bf550ab5a62229b8aca3c3c12.jpg)