Ebru

Highlights

• Marbling that behaves like marbling. Every drop is a closed polygon and every tool is a closed-form deformation of the whole surface (the "mathematical marbling" model): a new drop pushes older paint outward in rings, the awl drags a chevron wake behind it, the comb pulls twenty-five tines at once. Colours never mix into mud because each band stays its own polygon. The same deterministic simulation runs for the player, the targets and the bot.
• 18 lessons in 3 chapters. Basic patterns (battal, gelgit, şal, bülbül yuvası), combed patterns (taraklı, kılçıklı, wavy and double combing, hafif) and flower ebru (hatip, tulip, carnation, hyacinth, daisy, poppy). Each lesson unlocks tools and pigments and starts with a short TR / EN technique note from the master on a card over the tray.
• One click to the water. Play drops you straight into the first unsolved lesson; the master's note fades at your first stroke, and lessons 1-3 show the first stroke of the recipe as a ghost on the water.
• The master's critique. The match score already knows how much of each pigment you used and where its centre is; v2 reads it out: "Add more Red ochre, upper right", "Lamp black is not in the target", live under the tray and on the result card. The rim of the screen glows at 80 % and a chime rings at 90 %.
• Master's seal. A lesson solved at 90 % or better, within par and without a hint earns a red seal; 18 seals rank you from çırak (apprentice) through kalfa (journeyman) to usta (master). The 54 stars are unchanged.
• Provably solvable targets. Every target is a recorded stroke list replayed in the same simulation; the live match % compares the tray with the target, and the hint replays the next stroke as a ghost on the water.
• Played by a bot. ?auto plays every lesson through the same stroke API as a player, with a small hand tremor. Measured: 18/18 lessons solved, 48/54 stars, 12/18 seals, 60 fps on an Intel UHD 620, 7-10 draw calls.
• Free tray, water thickness, gallery and book covers. Paint whatever you like on thin, medium or thick water (drops spread wider and the awl drags a broader wake on thin water), lay the paper and keep up to 12 sheets in the gallery; bind any sheet into a book cover (leather spine and corners, the sheet as the board paper). Your last sheets hang to dry on the line behind the table, and the workshop kitten dozes on the table edge.
• Paint rasterised on the GPU. The polygons are filled with a signed-winding stencil pass into a multisampled render target, so a tray with a hundred thousand points still runs at 60 fps on an Intel UHD 620.
• One file, made in code. One index.html with Three.js r170 from a CDN; every mesh, texture, icon and sound (drips, swishes, paper rustle, a ney and kanun loop) is generated in code.

How to play

[!TIP] Goal: make the tray look like the target in the corner. Reach 80 % match and lay the paper. Three stars per lesson: solve, reach 90 %, and stay within par strokes.

Pick a tool and a pigment from the tray at the bottom. Drag over the water: the brush sprinkles drops as you move, the awl (biz) and the comb (tarak) drag the paint with them, the big drop opens a wide circle for flowers. Press H to see the next stroke of the master's recipe as a ghost. When the match reaches 80 %, lay the paper with Enter.

• The lessons are a data table of recipes in the code; targets are generated by replaying them when the game loads.
• Undo keeps the last 12 strokes; clearing the tray is undoable too.
• In the free tray, Enter lays the paper and saves a 256 px JPEG of the sheet to the gallery (localStorage); the bind button (or B) turns the sheet you just saved into a book cover, and every gallery sheet has a bind toggle.
• Water thickness (free tray only, T cycles it) scales the drop radius and spacing and the awl / comb falloff; the lessons, the targets and the bot always use the medium table, so every target is bit-identical to v1.
• The master's seal needs 90 % match, par or fewer strokes and no hint. The free first-stroke ghost of lessons 1-3 does not count as a hint; pressing H does.
• "Did you know?" facts on the title and result cards come from the UNESCO Representative List entry for ebru (inscribed 2014): pigments on thickened water worked with a brush, the pattern taken up on paper, used on book covers and bindings, at least two years to learn the basics, passed from master to apprentice. Source links are in CREDITS.md and in the code.

Controls

Action	Mouse / touch	Keyboard
Stroke	drag on the water
Tool: brush, awl, comb, big drop	tool tray	1 2 3 4
Colour	swatches
Zoom	wheel, pinch
Undo / clear the tray	HUD buttons	Z / R
Lay the paper	tray button	Enter
Hint (ghost of the next stroke)	HUD button	H
Lesson map	HUD button, pause menu, result card
Pause	HUD button	P / Esc
Music / effects / language / fullscreen	HUD buttons	M / X / L / F
Water thickness (free tray)	thin / medium / thick switch	T
Bind the last saved sheet (free tray)	tray button	B
Gallery (free tray)	tray button	G

Settings are saved in localStorage under arena.ebru.settings; stars, seals and the current lesson under arena.ebru.save, the best star total under arena.ebru.best, the gallery under arena.ebru.gallery and the bound flags under arena.ebru.bound (v1 saves load unchanged). Turkish is the default language (English when the browser is not Turkish); phones start on the Low tier.

Flag	Effect
?auto	a bot plays all 18 lessons to the ending, making the recipe strokes through the same stroke API as the player, with a small hand tremor (&jitter=N units, default 6)
?debug	fps, JS ms per frame, draw calls, triangles, polygon and point counts, GPU name and JS errors on screen; window.ebruSim(seconds) and window.ebruDebug
?sim=N	fast-forward N seconds before the first frame
?low	shadows off, pixel ratio 1, 512 px paint target, half the dust
?lesson=N	open lesson N (1-18) directly; ?free opens the free tray
?lang=en / ?lang=tr	language
?nosave	do not write to localStorage
?noassets	skips the three mascot PNGs (the only asset files); everything else is generated in code

The live state is on window.ebru (state, lesson, match, strokes, stars, seals, rank, thickness, critique, polys, points, fps, calls, bot log, errors, assets).

Screenshots

Running locally

Serve the folder over HTTP (ES modules do not load from file://):

python -m http.server 8000

then open http://localhost:8000/.

How it was made

Built by Claude Fable 5.1 with Claude Code from one prompt: prompts/ebru.md. Everything is generated in code:

• Simulation: a drop at C with radius r moves every point P to C + (P - C) * sqrt(1 + r² / |P - C|²); the awl and the comb move points along their motion by exp(-d/λ) across the path and a window along it, applied in fixed 8-unit steps so the result does not depend on the pointer event rate. Polygons are resampled after every step and clamped to the tray walls; a point budget coarsens the sampling when the tray gets busy.
• Match: the tray and the target are rasterised small on the CPU; the score is a lenient colour comparison on a 16x12 grid plus, for every pigment the target uses, how much of it the player used and where its centroid is.
• Paint rendering: one dynamic BufferGeometry of triangle fans with three material groups per colour (stencil +1 on front faces, -1 on back faces, colour quad where the stencil is non-zero), rendered in one call into a 4x MSAA render target that textures the water.
• 3D: a flat-shaded, vertex-coloured workshop merged into one draw call, instanced pigment jars, one shadow-casting directional light over the table, soft-sprite dust in the window light, the active tool following the pointer and a paper sheet that drops, takes the pattern and lifts. About 7-10 draw calls per frame (6-9 without the kitten).
• Audio: Web Audio only: drips tuned by drop size, a band-passed swish that follows the awl's speed, paper rustles, and a slow ney phrase in a Hicaz-like scale over a drone with a kanun answering.

v2 update

Upgraded by Claude Fable 5.1 with Claude Code from prompts/ebru-v2.md:

• Play goes straight into the first unsolved lesson; the master's note is a card over the tray that fades at the first stroke; lessons 1-3 show the first recipe stroke as a ghost and pulse "Lay the paper" at 80 %. The map stays one click away from the HUD, the pause menu and the result card.
• The master's critique: the worst two per-pigment deviations (unused, too little, too much, wrong place, not in the target) as a live line and on the result card, with a rim glow at 80 % and chimes at 80 / 90 %. The critique classes pixels against the pigments actually in play, so antialiased edges never name a colour nobody used.
• Master's seals (90 %, within par, no hint) and the çırak / kalfa / usta rank on the title, map, result and ending; stored as seals in arena.ebru.save.
• Water thickness in the free tray (thin / medium / thick scales the drop radius, spacing and the awl / comb falloff); lessons and the bot keep the medium table, so the targets are unchanged.
• "Bind it": a 2D book-cover composite of a sheet on the result card, in the free tray and in the gallery; bound flags in arena.ebru.bound.
• Notes cleaned of unsourced names and dates; "Did you know?" facts from the UNESCO entry on the title and result cards.
• The arena's Turkish Van kitten: asleep on the table edge (a sprite, one extra draw call) and cheering or thinking on the result card. Measured after the upgrade: bot 18/18, 48/54 stars, 12/18 seals, 58-60 fps and 7-10 draw calls on the UHD 620, zero JS errors with and without assets.

Ebru is part of the Claude Game Arena series, where each game is built by a Claude model from one prompt. The other games: Hisar · Çay Ocağı · Çini Ustası · Martı · Kervan · Dolmuş · Peri Golf · Mehter · Boğaz Vapuru · Simit Fırını · Karagöz · Lale Bahçesi

Round 5: Kapadokya Balonu · Kırkpınar · Çarşı Kaçışı

Round 6: Topkapı Gecesi · Hamsi · Pamukkale · Mimar Sinan

Türkçe

Ebru, eski bir ebru atölyesinde geçen 3D sanat bulmacası. Kitreli suya fırçayla toprak boya serp, bizle çiz, tarakla tara, lale ve karanfil aç; teknedeki desen ustanın hedefine %80 uyunca kâğıdı yatır. 3 bölümde 18 ders, her derste ustadan kısa bir not ve canlı eleştiri ("Daha çok Aşı kırmızısı ekle, sağ üstte"); ipucusuz ve par içinde %90'a ulaşan derslere usta mührü (çırak, kalfa, usta). Serbest teknede su kıvamı (ince / orta / kalın), 12 kâğıtlık galeri ve kâğıtları kitap kapağına ciltleme. Kurulum yok; masaüstünde ve telefonda tarayıcıda oynanır. Claude Fable 5.1 tarafından Claude Code ile tek bir prompt'tan yapıldı; v2 güncellemesi prompts/ebru-v2.md ile.

Oyna: https://furkiozknn.github.io/ebru/

License

MIT, see LICENSE.

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