I have only solved one puzzle in Prolog, but here it is: https://github.com/widforss/adventofcode/blob/master/example...

I choosed Prolog for that one as that meant I didn't have to implement the search algo, just state the problem in logic.

I'd love to but alas I don't have it public. Googling, I found a few other folks like this one:

https://github.com/Limmen/Advent-Of-Code16-Prolog

Don't know if this is "beautiful" prolog but the programs seem pretty short compared to what a typical AoC question is.