An Unexpected Wall── One Bug Found Mid-Implementation
Episode 08 “An Unexpected Wall — One Bug Found Mid-Implementation”
Future Gadget Lab Devlog — Building Gadget No.6, the Steins Gate Simulator
Published: May 27 (Wed), 2026 ／ JST 07:00
On the Third Pattern, Something Strange
The afternoon of the day rule adjustments were finished and Gadget No.6 v1.01 entered the test phase.
Daru tried a test pattern with extreme values on the three Worldlines —
“Wait… Worldline γ (green) disappeared.”
On screen, the third convergence arrow was not drawn.
α (blue) and β (orange) showed correctly. But γ alone — as if deleted from a Worldline.
Where the Bug Lived
Daru traced the code. The problem was in the weighted score calculation.
“`js
// The location (simplified)
worlds.forEach(w => {
if (w.score > 0) {
render(w);
}
});
“`
“If you put 1 on every axis, the cost axis (inverted) becomes 5, and it can cancel out with 0 on another axis — score sometimes lands exactly at 0.”
A rare case at the edge of the numbers. Maybe not one in a hundred users would hit it.
But when hit, one Worldline disappears.
The Fix
What Daru added was a single line.
“`js
worlds.forEach(w => {
if (w.score >= 0) { // > changed to >=
render(w);
}
});
“`
Daru: “Yappy. I just changed it to `>=`.”
Director: “The boundary of a Worldline is protected by ≧. One character makes the difference that saves the observer’s tool.”
The Temperature of Development Left in the Lab
After committing the fix, the third pattern was tried again.
γ’s Worldline was now heading properly to the convergence point.
A sigh of relief flowed through the lab.
Amadeus: “Catching these rare cases needs a third-party eye. That’s why I’m always attacking edge cases.”
Mayushii: “I’m glad the three Worldlines came back.”
What the Bug Taught
The fix was one character — but the lesson was heavy.
“The kind of moment a nonfiction series can write about. A hundred lines that ran smoothly, versus one bugged line and the moment of fixing it — the latter reaches the reader’s heart more.”
A new line was added to Daru’s notes.
“Implementation proves itself in the edge cases. Protecting the boundary condition is the observer’s responsibility.”
The coffee in the lab was getting cold.
But the release preparation for Gadget No.6 v1.02 started accelerating from here.
Next Episode
Episode 09 “The Teaser Post, the Worldline Begins to Move” — Tomorrow morning at 7:00 JST.
The day before the final episode.
Three days of teaser posts begin to move the Worldline.
Related Gadget
Gadget No.3 “Timebox Ma-Kinky” — Design 90 days in a 13-week grid.
Edge-case-aware design — the same as the planning gadget.
On sale at Coconala (JP) for ¥1,000 — search “Ruruo / Future Gadget”.
Existing Lineup
- Search “Ruruo / Future Gadget” on Coconala (Japanese marketplace)
- Full episode list: ruruob.com/serial/en/
- Japanese edition: 日本語版
© Ruruob ／ Future Gadget Laboratory ／ #FGL-Devlog ／ Episode 08
EL PSY KONGROO
WORLDLINE OBSERVATION / EP08
How to break the unexpected wall?Your vote rewrites the opening of the next episode.
▼ If you stop reading here
From Ep.08 alone, you became an observer who witnessed the unexpected wall surfacing. Whether you continue or pause here is the observer’s choice.
If it resonated:
- Tweet your thought with #FGLDevlog
- Pin this article on Pinterest
- Ep.09 ‘Teaser Post — Worldline Moves’ lands on the beta worldline tomorrow at 7am JST. Come back if curious.
Every observer shifts the worldline. Thank you for observing.
▼ Existing Lineup
The five existing gadgets and the integrated set are on sale at Coconala (JP).
- Search “Ruruo / Future Gadget” on Coconala
- All episodes: serial top
- Japanese: 日本語版
— ruruo, the operator of ruruob.com
米国Amazon物販を日本人視点で。為替・関税・輸入手間を込みで考えるレビューを継続しています。 / Reviewing US Amazon products from a Japanese consumer's perspective.
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