The Idea
Somewhere along the way, everybody agreed that times tables stop at 10×10. Maybe 12×12 if your teacher was ambitious. And then… nothing. There is an invisible wall at the edge of the multiplication chart, and past it lies the land of “just use a calculator.”
A kid (or an adult!) who can casually knock out 14×16 in their head walks around with a genuine superpower not because those facts come up constantly, but because of what knowing them does to your confidence with numbers.
So that is the app: a multiplication trainer that goes all the way to 20×20. Twenty times twenty is a 400 square grid, hence the name Times Table 400.
Vibe-Coding, Round Two
If you read the Weather Gnome post, you know the setup: I am not a programmer, and I build apps by describing what I want to Anthropic’s Claude Code (the Fable 5 model) the way I would explain a project to a friend, then iterating stubbornly until it exists.
This time it went fast. The whole space-themed skeleton — an astronaut mascot named Mochi, quiz “missions,” a Warp Manual full of mental-math techniques, a Galaxy Chart that tracks your mastery across the grid, a 60-second Hyperspace Sprint mode — went from idea to a working build on my phone in a day. Sounds, celebration screens, the works.
The second app is dramatically easier than the first. Partly because I knew the ritual this time (certificates, provisioning profiles, App Store Connect, the Apple bureaucracy from last time), and partly because the tooling from Weather Gnome carried over. The scripts and checklists we built shipping the first app became a little reusable kit, and app number two got to ride on it.
The Code Was Easy. The Teaching Wasn’t.
Here is the lesson that surprised me: for an education app, writing the code is the fast part. Deciding how to teach is the slow part, and the AI cannot decide that for you.
Does a beginner need every fact introduced with a little step-through derivation, or is that condescending for 2×3? (It is condescending. Early testing made that obvious the app was dutifully teaching facts a kid already knew cold, so we gated the intros to skip trivial and already-mastered material.) When should a missed fact come back around? What does a technique lesson for the 17s even look like? Those are curriculum questions, not code questions. The AI drafted options in seconds; choosing what was actually good for a learner was the real work.
Vibe coding has not changed my old conclusion, just sharpened it: the model writes the code, but the judgment is still your job.
Apple Wanted Receipts
Weather Gnome sailed through review in two days. Times Table 400 got stopped at the border.
Instead of an approval, I got a “Guideline 2.1 — Information Needed” letter: seven questions about the app’s purpose, audience, content, and features, plus a request for a screen recording of the full user flow — captured on a physical iPhone, not a simulator.
This turned out to be a great example of where the human is still very much in the loop. Claude drafted a thorough, honest reply to all seven questions in minutes. But no AI could hold my iPhone and record the video that was me, on Do Not Disturb, narrating my way through a first-run setup and a multiplication mission like I was filming a nature documentary.
The other lesson: App Review is a conversation, not a verdict. I replied to the existing review instead of panicking and resubmitting, answered everything directly, attached the video and the review resumed.
Approved!
And then, today: approved, released, live. Times Table 400 is on the App Store, free, no ads, no accounts, works fully offline. An iPad version is already built and queued up next.
Some Thoughts
- Arbitrary limits are often just defaults. Nobody decided 10×10 was the edge of human capability; it is just where the chart in the classroom stopped. Build past the wall in apps and elsewhere!
- Tools compound. Everything painful about shipping app #1 became a script or a checklist for app #2. The first app is the expensive one.
- The AI writes the code; you own the curriculum. For anything meant to teach, the design of the learning is the actual product.
- When Apple asks questions, answer them. Promptly, honestly, with evidence. A review holdup is a request for information, not a rejection.
- Still budget for the boring 20%. Some things never change.
If Weather Gnome proved that a non-programmer can ship an app, Times Table 400 proved something better: the second one is easier, and the third one will be easier still. The wall is made of paper.
Times Table 400 is on the App Store now — go learn what 13×17 is and feel unreasonably powerful about it!