Antiphon

A conversation is not a question. It is an arc: it opens somewhere cheap, warms up, turns once, goes deep, and lands somewhere easy. Antiphon builds that arc for the people actually at your table.

Why not another deck of cards

Every deck of conversation cards has the same problem: the cards have nothing to do with each other. You draw a shallow one, then a devastating one, then a shallow one. There is no shape — and a conversation without a shape does not go anywhere.

Two products were measured before this one was designed. The category's most downloaded app ships 2,150 fixed questions in 46 categories; a newer competitor ships 180 base cards plus three packs of 90. Both are decks. Neither mentions group size, familiarity, the time you have, or how loud the room is — and none of them have a rule for how a conversation should end.

Ten rules, and every one is measured

1	The opening is concrete and cheap. Nobody is exposed in the first minute.
2	The ceiling comes from how well you know each other: strangers 0.35, acquaintances 0.55, friends 0.75, close 1.00.
3	The arc lands. The last move is always easier than the deepest one. No other app in this category has this rule.
4	Exactly one turn. Five would be an interrogation.
5	No two moves in a row share a medium, and long arcs use at least three of the four.
6	Everyone speaks — measured, not "usually".
7	Above six people, at least 40% of moves are pair splits: pairs run in parallel, a round of six takes four minutes.
8	The time budget is kept to ±15%. In practice the measured deviation is 0%.
9	The room constrains: no turn-taking where it cannot be heard, no screens while walking.
10	Deep moments go to pairs or to one person, never around the table. Being asked in turn, in front of eight people, what you have forgiven yourself for is exactly how an evening freezes.

The numbers

arcs generated across the full parameter space	213,840
rule violations	0
arcs from a generator that knows everything except the shape that break a rule	99.95%
time-budget deviation	0.0000%
deliberate defects the test suite has to catch	67 of 67

That last row matters more than it looks. Tests being green does not mean they measure anything. Sixty-seven deliberate, meaningful defects are injected into the core one at a time; every one must turn the suite red. Nine of them escaped the first time, and nine tests were written because of it.

Bring your own material

A word, a photo from your phone, or whatever is playing. The arc is built from it — and all of it is processed on your device. The photo is read by Apple's Vision framework and never leaves; the music is measured for tempo and brightness and is never recognised, never recorded, never stored.

No account. No server. No internet.

There is nothing to sign up for, nothing that syncs, and nothing that is kept. When the evening is over, the app remembers none of it.

This is not a promise, it is a build gate: the archive fails if URLSession, Network, CFNetwork, WKWebView, AuthenticationServices or CloudKit appear anywhere in the app.

Price

Free: one complete arc a day — not a preview, not a locked version. One purchase, once, unlocks unlimited arcs, your own word/photo/music input and every language. No subscription: a thing you use at dinner is not rented.