It has gradually become a sport to wear the ugliest Christmas themed round sweaters around the world. Today, December 18, is even celebrated International Ugly Sweater Day.

Therefore, the Norwegian company Computas decided to use artificial intelligence to generate the ugliest Christmas patterns, and knit the sweater itself.

– We usually use our expertise in AI and machine learning for more serious tasks. Now we want to test which patterns machine learning suggests are ugly Christmas sweaters. We should be allowed to have fun in the run-up to Christmas, says managing director Trond Eilertsen, wearing his Christmas sweater.

The most common motifs found by this algorithm include snowmen, snowflakes, and the colors red, green, and blue.

– We extract thousands of Christmas sweater images from the internet which we feed through a machine learning service that interprets and identifies the various elements. The goal is to find the most frequently occurring components and colors, and use that as a database, said Simen Selseng, data scientist at Computas.

Computas uses, among other things, an interactive drawing program called Google QuickDraw. Here, people have drawn millions of quick pictures with around 300 Christmas motifs

– Basically, computers don't know anything about Christmas, so we put together examples of what Christmas is like. “We did that, some of which came from components we discovered in the feasibility study,” explained Selseng. With this knowledge, the system can draw new sketches of snowmen and snowflakes that look human-made but have never been drawn before.

All the little elves come, come on Christmas Eve

Computas also loaded the system with all the Norwegian Christmas songs they could find digitally.

– One of the attractions here are the new verses that humans could not necessarily create, says Selseng, who is satisfied with the text they came up with and which now adorns the front of the jumper: “All the little elves come, come, come Christmas Eve” . It doesn't make sense, but it's a very good text, isn't it! Almost makes you want to hum.

The jumper eventually got its own knitting pattern, and was knitted by Computas employees themselves. If you want to knit your own sweater, that's okay sweater recipe here.