What’s new
The site is early, and it is written by one person, so it grows the way one person can: a track at a time. Rather than promise what is coming, this page records what actually arrived, newest first. There is no newsletter to join — this page is the announcement.
—6 November 2026
- 90 new daily puzzles, enough for every day until late January. The first 30 had started to repeat; from today every day is a new one again. As before, every answer was checked by running the code.
—29 September 2026
- A daily puzzle: one short snippet, four answers, three tries, and the same puzzle for everyone that day. Every answer was checked by running the code. Your streak stays in this browser.
—21 September 2026
- A way in for first-time visitors: the index opens with three gentle exercises rather than 146 rows and no starting point.
- Every page can now send a report in one line — the exercise you were on comes with it. A diagnosis that misreads your code is the single most useful thing anyone can tell me, and there was no way to tell me.
- Around the site: an eye saver colour theme for long evenings, and the pages that explain the place — about, help, terms, privacy and this one.
—14 September 2026
- Three data tracks, 38 exercises: working without a library (nothing to download), arrays with numpy and tables with pandas. Each page says up front what it will fetch and how big it is.
- The four pandas mistakes that make real code wrong by accident — writing to a copy, a merge that multiplies rows, a groupby that drops your missing keys, and arithmetic that aligns on the index rather than the position.
—11 September 2026
- The catalogue reached 146 exercises across 14 tracks, every one with a worked example, a four-rung hint ladder, a published solution and the note about when not to write it that way.
—9 September 2026
- Two more kinds of exercise beyond writing a function: debug, where the code runs and lies to you, and refactor, where it passes every test and is still not done.
- A practice record that remembers which mistakes keep catching you, not just which exercises you finished.
- Prerequisites shown on every exercise — as suggestions. Nothing here is ever locked.