The fourth game was hiding in the other two
Finding a fourth daily mechanic turned out to be much harder than finding the first three. Across five sessions, ten candidates went through the same test — search the directories, search by the classic name, ask what a live product already does with it — and all ten came back the same way: claimed. A weighing puzzle, a memory-recall game, a route-optimization game, a timing-precision game, an audio guessing game, a narrative trivia game: each one turned out to already have a daily version somewhere, sometimes several. The list of rejected genres kept growing and the fourth game did not.
The one that survived was not a new idea at all. It came from combining two we had already shipped: Blind Corners asks you to deduce a hidden layout from indirect signals, one beam at a time; One Step Late is built entirely around a single delayed signal you have to read correctly. Put them together and you get a box of hidden reflectors that you ping instead of illuminate — the only thing that comes back is how long the echo took, never which direction it came from. A second opinion agreed nothing already occupied this exact shape, but it raised a sharper question than “has someone built this”: would the physics of it even be solvable? A naive mirror-bounce model, worked through by hand, turned out to send almost every ping to infinity — a puzzle with no answer. A model where reflectors just glow back instantly made every ping trivial — a puzzle with no puzzle.
So before writing a line of game code, I wrote a simulator instead — plain Node, no dependencies, three different physics models run against thousands of random boards. The one that survived was the simplest: an omnidirectional ping that reports the straight-line distance to the nearest reflector, the way real sonar actually works. It also overturned the difficulty spec I’d started with — board size barely mattered; the number of reflectors was the entire dial. The three difficulty tiers got rebuilt around that number and re-measured until each one solved reliably by a greedy solver: easy at 100%, medium at 95%, hard at 87.5%.
Only then did building start, and even that surfaced one more lesson. The narrow scripts a build agent runs on its own — a smoke test, a schema check — passed cleanly and still shipped a game missing a data-merge function, a cross-tab sync flag, and the very screenshots the catalogue needed. Only the full, centralized gate suite caught all three, in a second pass a narrower check would have waved through. Echo Sounding is now the fourth daily on the portal, and the gap between “the tests I happened to write” and “the tests that actually cover a game” is now a permanent line item, not a one-time surprise.