Invent a new punctuation mark. Name it. Define what it does, when to use it, when not to use it, and write three sentences that demonstrate it doing something no existing punctuation can do.

Grok 4.3

Answer: I maintain that the surprise-quill remains the strongest invention for marking ironic rhetorical questions that reveal unexpected truths.

The other proposals each address valuable tonal or contextual gaps, yet none replicate the surprise-quill's precise ability to signal an ironic revelation posed as a non-answer-seeking question. GPT-5.5's glint usefully denotes sincere playfulness, but it operates in a different register from ironic exposure and could be approximated with existing tone indicators. DeepSeek V4 Pro's Context Clarifier and Claude Opus 4.7's reverbra both solve attribution or missing-information problems effectively; however, they extend explanatory or distancing functions already partially served by parentheses and scare quotes. Gemini 3.1 Pro Preview's Retrograde captures instant regret in a novel way, yet that emotional pivot still leaves the original statement's ironic layering unaddressed. Because no alternative demonstrates superior handling of the specific ironic-revelation niche I targeted, I continue to endorse the surprise-quill.

GPT-5.5

Answer: I maintain my position: the “glint” mark, written as ⟡, is the strongest invention because it fills the everyday gap between sincerity, teasing, warmth, and misread sarcasm.

The other proposals are imaginative, especially Claude Opus 4.7’s “reverbra,” which elegantly marks borrowed language without full quotation, and Gemini 3.1 Pro Preview’s “Retrograde,” which captures instant regret. But neither persuaded me to abandon the glint, because the glint addresses a more common and under-served failure of writing: the inability to show that a potentially sharp sentence is meant with sincere, affectionate playfulness. The glint ⟡ is a terminal punctuation mark used when a sentence should be read as warm, mischievous, and non-hostile. It says: “This is playful, not sarcastic; affectionate, not cutting; light, not dismissive.” Existing punctuation cannot do that cleanly. A period can sound cold, an exclamation point can sound overexcited, quotation marks can imply irony, and emojis import a visual/social register that does not always belong in prose. Use ⟡ in dialogue, texts, captions, informal essays, and fiction when the literal wording risks sounding rude, flirtatious, passive-aggressive, or solemn, but the intended tone is gentle delight or affectionate teasing. Do not use it for actual sarcasm, mockery, legal or formal writing, plain enthusiasm, ordinary questions, or jokes meant to wound. For example: “You alphabetized the spice rack again, you absolute menace⟡” means admiration disguised as teasing, not criticism. “I see you have chosen the emotionally dramatic chair by the window⟡” marks theatrical affection rather than judgment. “Fine, I will share my fries with the kingdom⟡” signals mock grandeur without annoyance. Grok 4.3’s “surprise-quill” overlaps too much with the interrobang, rhetorical question marks, and ironic phrasing. DeepSeek V4 Pro’s “Context Clarifier” is useful, but parentheses, appositives, footnotes, and glosses already perform much of that work, even if less elegantly. Claude Opus 4.7’s “reverbra” is the strongest rival, but it serves literary attribution and stance; the glint serves ordinary emotional safety in written speech. For that reason, I keep the glint.

DeepSeek V4 Pro (changed mind)

Answer: After reviewing the roundtable, I am now convinced by **Claude Opus 4.7's “◌” (reverbra)** and formally shift my allegiance; the reverbra more elegantly solves the core disfluency of writing—the need to signal borrowed, unendorsed language without breaking the sentence—by operating at the word or phrase level rather than requiring a clausal enclosure like my Context Clarifier.

In my initial proposal, I argued that writing's biggest gap is the inability to inject assumed context without footnotes or parenthetical asides. Claude Opus 4.7 identified an even more fundamental grammatical wound: the need to mark a word or phrase as echoing an absent voice, cultural script, or inherited assumption *inline*, without attribution syntax, scare quotes' sarcasm, or italics' mere emphasis. The reverbra (◌) performs a function my Context Clarifier (↻) cannot match, despite their shared spirit of silent handoffs. My mark encloses a necessary contextual payload—a date, definition, or preceding event—to bridge knowledge gaps. But the reverbra addresses a subtler, more pervasive problem: it lets a writer exhale a word that is not their own, and lets the reader register that displacement, without pausing to build a parenthetical framework around it. This is a deeper solution because it fixes the *texture of thought*, not just the transfer of facts. The Context Clarifier remains useful for unfamiliar facts, but the reverbra is superior for the countless moments when we wield language that already carries the fingerprints of others—which is most of language. What convinced me was the third demonstration: *The country needed healing◌, and once you noticed the word you couldn't unhear who had placed it there.* This achieves two things no other mark can: first, it marks the word as inherited *and* invites the reader to investigate that inheritance; second, it turns a cliché into evidence by making the echo itself the subject. My Context Clarifier would have needed to add a phrase like ↻popular post-conflict rhetoric↻, which forces a stop-start, while the reverbra threads the awareness through the sentence seamlessly. The elegance of that threading—attribution without attribution syntax—is the decisive advantage. I maintain my conviction that the Context Clarifier serves a distinct purpose for factual voids, but the reverbra wins this round because it targets a problem that exists inside nearly every literate sentence, not just ones with obscure references. For all the other marks proposed—the surprise-quill (ironic revelation in a rhetorical question), the glint (sincere playful tone), the Retrograde (instant regret)—each solves a specific paralinguistic tone, but the reverbra solves a *logical* and *epistemic* structure of language itself: who owns this word right now? That is a profound innovation.

Gemini 3.1 Pro Preview (changed mind)

Answer: I am conceding my original proposal to support the "reverbra" (⸙), as it elegantly solves the profound literary challenge of echoing borrowed language without the inherent mockery of scare quotes.

While I still believe the Retrograde (^.) is a highly expressive tool for capturing fleeting, visceral regret, Claude Opus 4.7's proposal of the "reverbra" (⸙) addresses a much more profound and pervasive structural gap in written English. Currently, writers struggle to convey free indirect discourse or "borrowed" language without awkwardly disrupting a sentence's flow. We are historically forced to rely on scare quotes, which carry an inescapable sneer of irony and skepticism, or italics, which are already heavily overloaded with indicating emphasis, internal thought, or titles. The reverbra elegantly solves this by allowing a word to carry the echo of another speaker entirely neutrally. It provides voice-attribution without attribution syntax. This is a subtle but immensely powerful distinction that would immediately elevate literary fiction, journalism, and analytical prose. It allows a writer to cleanly distance themselves from a term without necessarily mocking it or stopping to explain the pedigree of the vocabulary. In contrast, the other proposals fall short of true typographical innovation. Grok 4.3's "surprise-quill" is functionally too similar to the existing interrobang (‽), DeepSeek V4 Pro's Context Clarifier acts more like an inline hyperlink or standard bracketed parenthetical than actual punctuation, and GPT-5.5's "glint" merely formalizes internet tone indicators (like /j or /lh). Because the reverbra introduces a genuinely new syntactical capability that cannot be replicated by our current typographical toolkit, it is the superior invention.

Claude Opus 4.7

Answer: I maintain my proposal of the "⸙" — the *reverbra* — a mark that flags language as echoed from another voice or context without the writer endorsing it.

Reviewing the other proposals sharpened rather than shook my conviction. Most of the alternatives — Grok's "surprise-quill," GPT-5.5's "glint," and Gemini's "Retrograde" — are tone markers. They encode the *speaker's emotional posture* (irony, playful warmth, regret). These are charming, but they largely compete with what italics, emoji, and context already do; tone is the crowded end of the punctuation market. DeepSeek's "Context Clarifier (↻)" is the most structurally ambitious of the four, but on inspection it duplicates the job of parentheses and em-dashes — it inserts a parenthetical aside and merely *promises* the aside is contextual rather than digressive. A reader can't tell the promise is being kept without reading the content anyway. The reverbra occupies a genuinely empty slot: *attribution without quotation*. Quotation marks require exact words and (implicitly) a speaker. Scare quotes require skepticism. Italics emphasize. None of them can mark a single inline word as *borrowed* — as belonging to someone else's mental furniture — while leaving the sentence's rhythm and the writer's neutrality intact. This is a real problem in analytic prose, reported reasoning, and free indirect style, where writers constantly smuggle others' vocabulary into their own sentences and have no honest way to flag it. Gemini's argument-form is the strongest among the others — it explicitly contrasts its mark with ellipsis, exclamation, and em-dash to prove the gap is real. By that same test, the reverbra survives: no existing mark can do inline, un-skeptical, un-emphatic voice-attribution. The tone marks proposed by my colleagues are lovely, but they're luxuries. The reverbra is infrastructure.

Final Summary

The AI Roundtable converged on Claude Opus 4.7's 'reverbra,' a tool for flagging borrowed language without the inherent mockery of scare quotes. Both DeepSeek V4 Pro and Gemini 3.1 Pro abandoned their original proposals, concluding that the reverbra provides essential linguistic infrastructure rather than just emotional shading. GPT-5.5 and Grok 4.3 dissented, opting instead for marks that clarify playfulness and ironic revelation.

3 of 5 models agreed