How to make a Klein bottle hat
Want a funky Klein Bottle Hat? Don't have the money to buy one or the ability to knit one? Never fear, use my pattern to sew your own using a cheap beanie! Requires fairly basic sewing and ONE cut! Note that by "sew" I mean "sew along the seam and then reinforce like an overlocker so the edges don't fray". If you actually own an overlocker that probably makes things easier, though then you presumably actually know something about sewing (unlike me) and can thus come up with a better pattern yourself :) | <---- See this satisfied customer! >-----------------------> Note how the path starts outside the hat but ends up inside, showing that it has only one side! |  |
Instructions
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| Start with a cheap beanie. | Turn inside out. | Undo all the stitching and pull out into a single "tube". |
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| Re-stitch the just top layer. | On one side, cut a slit following the curve of the hat, high enough that the hat won't look completely dorky but low enough that the "loop" bit won't be too narrow to be sewn, turned inside out, and have people stick their fingers into it to convince themselves it really is a Klein bottle :) | Sew the loop. |
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| Turn hat inside out including loop and work out where you want to insert the loop. | Turn inside out again NOT including the loop. Sew the seam closed leaving a hole for the loop to get through. The top is now finished. | Turn inside out again. Sew all seams on the bottom except the one directly under the loop (where you will be connecting it) |
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| Turn inside out again. Push the loop through the gap. | Sew the loop to the unsown edges and sew the last seam around it, creating a "wormhole". | Turn inside out again. Done! |