I'm honestly pretty proud of my Advent contribution, it's not super deep or complicated but I've never done this puzzle type before and I feel like the solution is pretty fun. What time should it be posted? (It's 9PM on 12/10 where I'm at.)

Looking forward to it! Everybody has been posting on their designated day in local time, I think typically in the morning. I think it's pretty much up to you.

Sounds good, I'll post it in the morning then :)

Looks great :) @Sciborg

^^^This!

@LukasRotter Argh! I did as well! It's right here in my spreadsheet as one of my attempts... Blast!

@Stiv :D

So that is finally it for the shack. Apologies for such a meh puzzle...it was my first of that type. Stiv did the bulk of the work...maybe makes sense to split the bounty and the answer? @LukasRotter what do you think?

@Sciborg: Day 11 is still open? That may change my afternoon plans :-)

Still open, we’re currently having a bomb cyclone storm here so I’ve been stuck indoors :p I really like the Advent Calendar project, everyone has made such cool stuff so far. If more slots are needed I can try and whip up a holiday grid deduction maybe?

I'll award the bounty to richard because finding the final step is what the bounty was for. He or someone else would have to gift an additional bounty to Stiv; I've learned my lesson and know my next bounty would have to be 300, which would get me into weird problems again :)

(I could of course just award a 150 bounty on some random answer from stiv)

I dunno

I think that makes sense. @Stiv: would you mind incorporating the final into your answer, and I'll give that the checkmark? Think we did something similar on your Connect Four puzzle between me and Deusovi.

@JeremyDover Sure thing, I'll sort that when I get a moment. No need for an additional bounty for me - the bounty was for making the final leap from my progress to the end and richard did that...

Dang. I found a game and rule set for Sciborg's puzzle that works perfectly for the first example but not the second... I was feeling so sure about it until I realised that on turn 5 Alice could say (e.g) "It's Gonna Be a Cold, Cold Christmas" which is actually a winning position for her under my game and rules... Now I can't unthink it and find my way to an answer! I've got puzzle-blindness!!

@Stiv I feel that pain. It can be so hard to dig out from a blind alley.

@JeremyDover Answer updated, puzzle put to bed!

@Stiv: Yes! The final message was more appropriate in mid-2020 when I wrote it. Thanks so much for bearing with it.

Ah, yes, of course :) Nice to see it finally solved - I can clear a little bit of space in my brain now...

@Stiv I will confirm that on turn 5, Alice could not say "It's Gonna Be a Cold, Cold Christmas" as there is a game rule that prevents her from doing so at that point.

But I think you are on the right track :)