Day 4 brought us back to grid problems. The task involved identifying paper rolls on a grid that forklifts could access, where accessibility is determined by how many neighboring rolls surround each position.
Grids are back, and so is my helper library fred.py. The problem is straightforward: count how many paper rolls (@) have fewer than 4 neighboring rolls in the 8 adjacent positions (including diagonals).
Day 3 was about powering an escalator using batteries. Each battery bank is a string of digits, and the goal is to select specific digits to form the largest possible number. Part 1 was straightforward. Part 2… took some work.
The task: from each string of digits, pick exactly two to form the largest possible two-digit number. For example, from 811111111111119, you’d pick the 8 and 9 to get 89.
Day 2 brought a pattern-matching problem in the gift shop database. The task was to identify “invalid” product IDs - numbers that consist of a repeating sequence of digits.
The first part required finding numbers where a sequence repeats exactly twice: 11 (5 repeated twice), 1010 (10 repeated twice), 123123 (123 repeated twice), etc.
My approach was regex-first. I default to regex when pattern matching is involved because it’s expressive and, when it works, elegant. I always think back at:
Day 1 of Advent of Code 2025 is in the books. The puzzle involved a safe with a circular dial numbered 0-99, and the goal was to count how many times the dial landed on 0 after following a series of rotation instructions.
Part 1 was pretty straightforward. Given a starting position of 50 and a sequence of left (L) and right (R) rotations, I needed to count how many times the dial ended up pointing at 0 after each rotation.
I’ve been running Immich for about a year now, and it’s been one of the most reliable self-hosted services in my setup. For photo and video backups, it has just worked—smooth uploads, a clean timeline, and the peace of mind of keeping my media under my own control.
Recently, I started experimenting with the new beta timeline feature. That’s when I hit my first real bump: smaller uploads worked fine, but larger images and videos would consistently fail. Since I run Immich behind Traefik, my first thought was that it might be a proxy-related issue.
