HN user
I think the issue with single-letter variables goes deeper than it just being unreadable (although its that too for someone that isn't "used to it").
For example there are issues with scope (what happens when I need a second or third "f" variable" and maintainability too (6 months from now I have to remember if "f" stands for "foo" or "file").
Thats how I counted them too. Start off with cell in top left corner and count 4x4 (16). Then make a 2sq cell and see that you can fit 3 of these across by shifting one cell at a time to make 3x3 (9). Same with 3sq cells (4) and 4sq cells (1) as the total size. Adding the inner ones is straightforward from there.
The real question is if its has an IPv6 address yet or if its still stuck using IPv4?
love it! great way to show progress while I keep working on another tab while waiting.