Show HN: Tetris Time

(tetris-time.koenvangilst.nl)

11 points by vnglst a day ago

It's almost New Year's and here's an original way to show the countdown using Tetris. I'm sure something similar has been done before, but I had a lot of fun building this (TDD style) using Claude Code.

After New Year's it can also function as a regular clock:

https://tetris-time.koenvangilst.nl/

For the impatient, it's possible to increase the speed using url parameters:

https://tetris-time.koenvangilst.nl/?to=2025-12-31T23:00:00....

ferguu_ 21 hours ago

Just letting you know, I think there might be something wrong with the code.

First time I ran it, just off the basic link, it eventually finished with a time of 36:42 (ran at 15:16)

Then I tried turning up the speed and it seemed to make numbers at first but erased its own progress with blank blocks, ending in gibberish.

Maybe another 100 prompts? haha.

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vnglst 20 hours ago

Oh that's weird. Are you sure it was the basic link and not the one with count down mode?
The one I shared in the parent is for the New Year's countdown: https://tetris-time.koenvangilst.nl/?mode=countdown&to=2026-...
The basic link should show the current time, even at high speeds: https://tetris-time.koenvangilst.nl/?speed=10
Oh wait, I just tested it on a higher speed (20) and I see what you mean. It's drawing over the existing Tetrominoes! I'm going to max the speed at 10.

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vnglst a day ago

The year is coming to an end, and looking back I had a lot of fun building quirky, fun, and insightful visualizations. Agentic coding agents have been hugely empowering for me. In 2024 it was “just” autocomplete on steroids. Now it feels more like conducting, directing the agents to go where I please. Often they’re impressive; sometimes they fail at the simplest tasks.

What worked particularly well here was a test-driven (TDD) approach. I asked Claude Code to focus only on the algorithm for selecting the next Tetromino (the Tetris blocks), starting with tests. After that, things went smoothly, though it still took many follow-up prompts (around 100) to reach the final result.

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