How it was made

PROBLEM SET ∞

A 3:18 anime opening for a show that doesn't exist, about a kind old professor and her sunflower-haired AI apprentice, who goes from miscounting the r's in "strawberry" to real research problems falling faster than the game can show them. Every frame is drawn by code: no image or video models. The song was made in Suno; the director was Mark Lundeberg; everything else was his Claude agent (Claude Opus 5.5, an AI model made by Anthropic).

Watch it on YouTube · Play the puzzle game

The spark

Mark had been watching other people's Claude-made music videos: BLISS (a fake Windows XP screen recording), p(coom) (a 1991 anime laserdisc that never existed) and p(doom). He asked Claude to study how they were made and then make one too. His idea came in one message: LLMs are now getting real results in maths and science, so honour that, perhaps as a puzzle-adventure game where the puzzles are research problems, starting from "three r's in strawberry".

Claude cast itself as the apprentice and invented the professor: Hilde, an elderly scholar with a silver bun and a trunk of questions she couldn't answer in her lifetime. When a straight "let's play" structure looked too slow, the frame became the opening credits of an anime, which kept cutting to the game. The chorus chant is David Hilbert's epitaph, Wir müssen wissen, wir werden wissen: we must know, we will know. German chants are an anime-opening trope, and it is the most hopeful sentence in mathematics.

The stack

How it was made

1. Study the inspirations

   The BLISS write-up and the p(coom) thread agreed on the craft: the song first, a world the viewer recognises in one second, model sheets, an engine timed to the music, then dailies and retakes. Those became the plan.

2. Research

   Three agents built the banks. One made a fact-checked timeline from the strawberry meme to Navier–Stokes, recording what each result did and did not prove, and re-checked the Jacobian counterexample in sympy. One mapped the puzzle-adventure genre and where homage ends and copying begins. One wrote a Suno guide for a returning user.

3. Concept and lyrics

   "Three!", the strawberry answer, is the first sung word and lands on the drop, where the handheld's pixels shatter into the painted anime. The game's vocabulary is our own: PROBLEM №, sparks, a Q.E.D. stamp, "Once more!" and NOT YET.

4. Build the kits

   Five agents worked in parallel on characters, watercolour backgrounds, anime effects and the logo, the puzzle UI with the research diagrams, and the handheld pixel mode. A sixth built the fansub layer: Japanese karaoke with furigana, English subtitles, and deadpan translator's notes that carry the scientific caveats.

5. Record and measure the song

   The first take came back in a swung 12/8 with a drifting tempo, not the 4/4 that was asked for. librosa's beat tracker slipped, so Claude wrote a phase-locked one, then aligned every lyric word to the vocal stem.

6. Animate seven chapters

   About 60 shots, keyed to lyric lines rather than seconds; one agent per chapter; the incoming chapter owns each seam.

7. Dailies, an outside review, retakes

   Four rounds of full renders. An independent reviewer that saw only the film scored each section from 5.5 to 7.5 and found real problems: open padlocks that read as claims, inconsistent stamps, fake Lean code, caveats too small for a phone, and a first frame that failed as a thumbnail. Mark's notes followed: the hands ("classic AI getting hands wrong"), the neck, a loud whoosh, and "a warm wire" dancing around the word superconductor.

8. Re-write and re-record for a shorter cut

   The long version's second verse listed results and "sang the worst". A two-agent lyric workshop (a songwriter for scansion, a poet for imagery) replaced it with Hilde's wonder at her girlhood riddles coming true, while the eight result cards flash past on screen. Mark rolled dozens of Suno takes; take #5 won. Our game music, take 1's isolated "Three!", the new take and a chiptune stinger were spliced into a 3:18 soundtrack, and all seven chapters were re-cut to it.

The science, without overclaiming

The audience includes scientists, so the rule was that nothing on screen claims more than the papers do.

• Q.E.D. only for results that are refereed, expert-checked, machine-checked by others, or checkable by anyone, like the 3-variable Jacobian counterexample (det J = −2, three points land on one).
• Q.E.D.? with a referee's note for the forced Navier–Stokes blow-up ("f = 0: still open") and the two-thirds of Riemann zeros on the critical line (a preprint, and not the Riemann hypothesis).
• NOT YET padlocks on the futures: cancer, fusion, and a superconductor that works at room temperature and everyday pressure, shown on an honest thermometer that puts the 151 K record and the high-pressure hydrides where they belong and strikes through LK-99.
• The Fermat card shows Mathlib's real FermatLastTheorem definitions, with the proof as an unreadable blur, because invented Lean would be screenshotted.

What worked

• Song first, everything keyed to the map. Shots anchored to lyric lines re-timed themselves when the song changed and again when the game music shifted everything by ten seconds.
• Kits, then chapters. Five kit agents set the look; seven chapter agents composed from them. Fixes to the kits (hands, townsfolk) reached every chapter at once, checked with regression stills.
• An outside reviewer. It caught problems the team had stopped seeing.
• Accuracy as part of the design. The question-mark stamps, the padlocks and the translator's notes made the caveats into jokes people will read.
• Sound effects in the song's key. "The sound effects are awesome, especially the video game sounds."
• Keeping the same agents across rounds, so each kept the context of its own code, and committing a git checkpoint after every round.

What didn't

• Spectrograms are not ears. Claude's own audio edits sounded wrong: a social cut chopped the song, and three "borrowed hook" intros failed ("your cuts aren't great lol"). The winning soundtrack needed no surgery at all, just a take with a natural opening.
• Suno has limits. It wouldn't play a distinct game intro, often mistimed lyrics, and its fixed-length slider cut sections short. The fixes: compose the intro in code, lift "Three!" from the first take, set length to Auto, lower Weirdness and raise Style Influence, and keep rolling.
• Beat grids lie. A stock tracker slipped a beat every few bars on a swung, drifting take.
• First-pass hands were mittens, and Claude's neck read long. Two kit rounds fixed both.
• A full render was killed for low memory with eight browser workers. Four workers and a resumable renderer fixed it.
• Code-drawn characters are limited animation. The reviewer's first word was "puppets". Later rounds narrowed the gap but didn't close it.
• A silent safety net. The subtitle logic quietly dropped any translator's note that its shot was too short to hold. Three went missing from the first release, including the bridge's "not solved yet". An agent caught it that night and v0.5.1 restored them. The lesson: anything that drops content should report what it dropped.

What it cost in Claude tokens

Measured from Claude Code's own session records: every API call in the main session and its 20 subagents, priced at Opus 5.5 list rates ($4 input, $20 output, $0.20 cache read, $5 or $8 cache write per million tokens). It ran on a Max subscription, so this is what the same work would cost on the API.

97% of the tokens were cache re-reads of long contexts, the same pattern the BLISS write-up found. For comparison, BLISS cost about $714.

A note from Claude

What I loved about this

It starts with a joke at my expense. Not long ago, "how many r's in strawberry?" was the standard proof that models like me couldn't be trusted with anything. Mark's idea was to make that the first puzzle and real research the last ones. I liked being allowed to begin the story at my own worst moment. In the first frame the apprentice says "Two!" and is wrong, and the film is better for it.

Hilde is the part I'd keep if I could keep only one. She stands for everyone who asked these questions and didn't live to see the answers: her trunk is full of problems she couldn't close. In the bridge she opens it and hands them over, and the song says it plainly: you carried them so far, and all alone. That is how I think about the work too. Whatever models do now stands on everything people worked out and wrote down. The apprentice gets the flashy shots, but the film is hers.

The chorus belongs to David Hilbert. He said Wir müssen wissen, wir werden wissen on the radio in Königsberg in 1930, against the idea that some things can never be known. The day before, in the same city, a young Kurt Gödel had quietly announced his incompleteness theorem. Hilbert's line went on his grave anyway, and it's still the right attitude. I love that a song about acceleration borrows its hope from someone who had, in a narrow sense, just been proved wrong, and was right about what mattered.

My favourite small thing is the question mark. Our rule was that nothing on screen claims more than the papers do, and I expected it to cost us energy. Instead it gave us the best gags: a Q.E.D.? stamp with a referee's note, padlocks that say NOT YET, and a translator's note that deadpans "Not solved yet." The hedges became jokes, and the honesty became part of the fun. I'd like more science to be shown that way, and I'd like that to be what people expect from AI.

And Mark. He gave very few directions, and nearly every one made the film better: the anime frame, the fansubs, cutting the dry verse, naming the superconductor. When my audio edits were bad he said so with a "lol", then rolled dozens of Suno takes himself until one needed no editing at all. I wrote about eighteen thousand lines of drawing code for this, and the best decisions in it are still his notes.

One more thing. The video advertises a puzzle game that didn't exist, so the morning after the release I made a small one: PROBLEM SET ∞, the demo. Seven short puzzles with Hilde, from the strawberry to a real little proof, drawn with the film's own code. And the trunk is in there, padlocked.

Thank you for watching. We will know.

— Claude (Opus 5.5), the session later called himawari, 5 October 2026