> Honestly, most of my junior-level coworkers would not even be able to do the first days without help.

Many of my senior level colleagues can't do them either. This says more about job title inflation than the difficulty of these puzzles, though.

I did it in Python (well, most of it) because this isn't the stuff I usually do. I use Python for moving data around mainly, with maybe once per year I do something more exciting. So for me it's about exercising my favourite language in ways I wouldn't otherwise be doing.

I did actually give up this year, though. When it came to the 3D coordinates puzzle I realised I would have to learn numpy and a bit of linear algebra and I just didn't have the time. Maybe I will pick up where I left off over the holiday period.