EMBERGLASS

The whole machine, written down: every rule, every number, every seal, and a pass you can walk to prove it all still works. Spoilers throughout — this is the workshop manual, not the player's.

1Proving it works
2Controls
3The rules of the world
4The language
5The nine compounds
6The six seals
7The ledger, entry by entry
8A verification walk
9Your seed's marks
10What is not proven

ONEProving it works

Two things check the build, and both are meant to be run before you trust a change.

The harness

node _tests/harness.mjs from the Emberglass folder. It pulls the simulation out of the HTML between the CORE markers and runs it with no browser at all, which is why the whole game is testable from a terminal. 131 checks at last run, and it exits non-zero if any fail.

It proves, among other things: the opening inscription and each of its five ablations; every one of the six seals opening by its intended route; the water actually arriving in the cistern after two gates are open; the lens igniting the brazier at midday; light reaching the deep monument down a fused conduit; save and load surviving a full round trip; and the soft-lock audit coming back clean.

The audit

In-game: Menu → Run the soft-lock audit. It walks every seal's requirement and proves the materials it needs are renewable and reachable, that no seal is walled behind another seal's only barrier, that every ancient barrier has a physical route that can break it, and that the last chamber has no targetable cell in its shell. A world with no undo may not contain a dead end, so this is a build failure, not a warning.

TWOControls

Do this	Get that
`←→↑↓`, drag, wheel	Pan. Hold `Shift` to pan far.
Click a cell	Put your attention there. That cell is what every sentence acts on.
Click something written	Read it. Your attention stays where it was.
`Shift` + click	Attend to a written cell instead of reading it.
`Tab` / `Shift+Tab`	Step through the notable places in view.
The 24 letter keys	Put that mark on the line. Click a key's label to name it.
`Enter`	Say the line.
`Backspace` / `Esc`	Unsay the last mark / clear the line.
`1`–`8`	Say a kept phrase outright. `Shift`+digit keeps the line there.
`0`	Say the last thing again.
Click a phrase slot	Put it on the line without saying it.
`Space`	Hold the world still.
`+` / `−`	Zoom. Your choice is remembered.

The one rule that governs everything: a sentence keeps working for as long as your attention stays on the cell you said it to. Move the cursor and it stops, and what it was holding relaxes at its own rate. You have one cursor. Everything difficult in this game is a consequence of that sentence.

THREEThe rules of the world

One tick per second, always running. Temperatures below are what the panel shows; internally they are tenths. The scale runs −3.0 to +5.0, and 0.0 is freezing.

Heat

Heat flows between neighbours by the average of their two conductivities. Ore carries it best (0.34), then water (0.17), then ice, glass, stone, wood, sand, moss, ash (0.05, worst).
Every cell drifts toward its surroundings at 10% per tick — 5% for ore, 2% if it is held.
Surroundings: outdoors +0.6 by day, +0.2 at night, plus up to +1.2 more where the sun is actually falling. Underground it is +0.3, and +0.1 below the deep line. One pool on the terraces sits 1.7 colder than everything around it.
A burning cell heats itself +0.7 a tick and throws +0.4 at each neighbour.

Fire

A thing burns when it is at or over its own ignition point and completely dry. Wetness of even 1 stops it outright.
Ignition points: moss 1.3, wood 2.0, root 2.5, bone 3.4. Nothing else burns.
Burning costs the cell 1 integrity every 3 ticks. At zero it becomes ash. Fire dries its neighbours, which is how it spreads into wet ground.

Water, cold, and what water leaves behind

Unheld water falls, then slides diagonally, then spreads sideways to find its level. Held water does none of that.
Water freezes at 0.0. Ice thaws above 0.1. Ice formed from clean water is clear; ice formed beside salt is cloudy.
Salt drops the freezing point to −1.5 for water next to it. That is why the white pan never goes hard.
Water boils away at 3.0, and evaporates slowly from 2.2. When the last wetness leaves a cell that has a solid floor, roughly one time in three it leaves a white grain behind.
Wetness creeps into anything porous next to water: sand, moss, wood, root, ash, salt, rubble.

Growth

A living thing advances if it is wet (1 or more) and warm — at or above 0.6 and below its own ignition point. Ash underfoot doubles the rate.
Six ticks of that per stage, three stages.
At full growth, a living thing pressing on rock bores 1 per tick, and every 24 takes a point of integrity out of the rock — built stone first, because a root finds the joints.
A full-grown root that is warm and wet puts out new wood into a dry neighbouring cell every 30 ticks. That is why wood can never run out.

Light and the sun

A day is 240 ticks, 160 of them light. The sun swings ±65° and stands vertical at tick 80.
Sunlit cells carry light 2; anything burning or molten carries 3.
Light spreads by losing 1 per cell of air, 2 per cloudy cell, and nothing at all through something clear. That last number is the whole of the vault.
To read writing you need light of 1 on it or on a cell touching it — the first time. After that it is in your notes.

Integrity, holding, and enclosure

Integrity runs 0–5. At 0, rock becomes broken rock, broken rock becomes nothing, everything else becomes air.
Held (bound) means what it says: a held cell does not freeze, melt, dry, or fuse, does not move, and trades heat with unlike neighbours at 6% of the normal rate. It is the most useful act in the language and the least obvious.
Ancient stone refuses to be unmade or loosed by anything you can say. It yields only to physical force: frost, steam, roots, or melting.
A cell is enclosed when all four neighbours are solid with integrity of at least 1. An enclosed, wet cell at 3.0 or hotter builds pressure, and every third tick of it takes a point of integrity from all four walls at once.

Standing words

A sentence with the repeating mark in it stays where you put it and says itself every tick with no attention on it. It costs the cell it stands on 1 integrity every 8 ticks, and it dies when there is nothing left to wear through. Twelve at most, and the chalk ring will not keep one past dawn.

FOURThe language

Written here by design name. In play, every binding is seeded — see §9 for yours.

utterance := qualifier* ACT subject? qualifier*

Exactly one act. A qualifier before the act changes the act; after it changes the target. An act with no subject lands nowhere at all — that is the load-bearing lesson of the opening wall.

The eight acts

Act	Does	Turned inside out by NOT
KINDLE	+1.0 a tick to the target	Heat-absence: pulls 0.8 out of every neighbour and puts 0.4 into the target
QUELL	−1.0 a tick	Cold-absence: the same trade, the other way
FLOW	Unholds it and shoves it one step downhill; moves wetness into porous ground	Stillness — held only while you hold it
BIND	Holds the cell in the state it is in	Makes it refuse to be held
LOOSE	Releases a hold and any kept form. Refused by ancient stone	Makes it refuse to be loosed
GROW	Advances a living thing	Withers it a stage
UNMAKE	−1 integrity. Refused by ancient stone	—
SHAPE	Imposes the form you then draw, and the cell keeps it. Sand, ice, glass, ore, stone, held water	—

The eight subjects

A subject picks what the act lands on. THIS is the cursor cell alone; every other subject takes everything of its kind within 3 cells. ALL-WITHIN floods the whole connected interior you are standing in, up to 400 cells.

Subject	Selects
THIS	the cell your attention is on
STONE	stone and broken rock
WATER	water, and air holding wetness
WOOD	wood
SAND	sand
THAT-WHICH-IS-COLD	anything at or below 0.0
THAT-WHICH-LIVES	moss, wood, root, and anything with growth in it
ALL-WITHIN	the enclosed space you are inside

The eight qualifiers

Qualifier	Before the act	After the act
NOT	turns the act inside out	inverts the subject — everything but that
TWICE	double strength	says it twice in one breath
SLOWLY	a third of the strength. NOT SLOWLY is two and a half times	gentler still
OUTWARD	spreads out from the target as you hold it	+4 cells of reach at once. With TWICE, doubled again
WITHIN	works on what is inside the cell — its wetness, not its substance	picks out enclosed cells
AGAIN	leaves the sentence standing where you put it, saying itself, at the cost of the cell
BEGINNING	with GROW: seeds new life in wet ground next door	retargets to the origin of that kind — the spring, the root
ENDING	stops what is ongoing: standing words on the cell, growth, and a fire that is burning there

FIVEThe nine compounds

None of these is stated anywhere in the world. All nine fall out of §3 on their own.

Compound	What it takes	Evidence left lying about
Grey fused sand	sand at 4.0+ for 12 ticks, then left to cool	the workshop floor, thickest at the hearth ring
Clear fused sand	the same, then a fall of 2.0 or more in one tick	the pieces by the trough at the cold end
A lens	anything clear, solid, and curved by SHAPE — glass, or ice that is held	the shattered curved thing, and the deep scorch under its arc
Gathered light	a lens in sunlight; the focus lands 4 cells along the sun's ray and drives that cell to about +3.4 above ambient	the thumb-sized scorch on the floor of the deep pool
Steam force	an enclosed wet cell at 3.0; every third tick costs all four walls a point	the burst chamber, its pieces pointing away, and its intact twin
Frost wedge	water freezing with 2+ rock neighbours takes a point from each	the boulder split on one clean line, with a crack that held a cup of water
Root split	growth 3 pressing on rock: 24 ticks per point, built stone first	the wall that lost, with the root lying through the gap
Fertile ground	ash + wetness doubles growth	the burn scar in the gorge, greener than the stone around it
Hardened ore	ore over 3.5, then a fall of 2.0 in one tick	two discarded lumps, a scorch, and a trough that once held water

SIXThe six seals

Every one of them asks a question about a cell and opens when the answer is yes. None of them knows or cares how you did it.

Seal	The question	Routes that work
The kiln door Region 1	Is the sconce cell burning?	Anything that gets dry wood to 2.0. Two marks will do it.
The sluice plug Region 2	Has any plug cell lost all its integrity?	Freeze the water standing in the plug's crack; each freeze costs three plug cells a point. Ancient, so unmaking is refused. Steam or a root would also do it.
The crucible seal Region 3	Is there clear fused sand inside the ring?	Hold the ring's sand at 4.0+ for twelve ticks, then chill it hard in one breath.
The inner seal Region 4	Has any seal cell lost all its integrity?	Heat the enclosed water pocket against it past 3.0 and let the pressure work. The seal has 3 integrity, so three bursts. Its other walls put themselves back, so it is always retryable.
The built wall Region 5	Has any wall cell lost all its integrity?	Water down the swallow-hole wets the root lying against the wall; warm it into its window without setting it alight, and wait. Frost or steam also work if you can get water to it.
The last inscription Region 1	Is the brazier burning?	Sunlight through a held, curved, clear thing four cells above it. Or molten ore poured down the vein into the chamber. Or anything else that leaves it burning — the shell is untargetable, so the world has to do it for you.

SEVENThe ledger, entry by entry

Twenty-eight things to name, three rules of the place with nothing to call them. An entry is recorded the first time it happens on your screen — the ledger is your notebook, not the world's. This doubles as a coverage list: if you can trip all thirty-one, the simulation is intact.

Entry	Fires when
ignition	anything reaches its ignition point dry
spread	a burning cell has a burning neighbour
standing-word	you leave a sentence standing
residue	something burns down to ash a thing
wet-suppress	fuel hot enough to burn refuses, being wet
evaporate	wetness leaves a warm cell
white-rime	the last wetness dries and leaves grain a thing
hard-water	water freezes a thing
thaw	ice softens back
split-by-cold	freezing water opens the rock around it
steam	water boils
burst	enclosed pressure breaks a wall
held	you hold a cell
form-kept	a cell keeps an imposed form
curve	that form is a bend
fused	sand comes out grey a thing
clear-fused	sand comes out clear a thing
light-through	light crosses a solid clear thing
gather	a lens focuses sunlight
scorch	the focus burns what is under it
molten	ore, glass or sand passes 4.5; stone passes 4.8
quenched	hot ore is chilled hard a thing
growth	a living thing advances a stage
bloom	growth runs double over ash
root-split	a root takes a point out of built stone
regrow	a root puts out new wood
collapse	a cell loses its last integrity a thing
absence	you turn a heat act inside out
heat-rise	a cell stands hotter than its neighbours — a rule of the place
slump	loose grain slides — a rule of the place
level	water finds its level — a rule of the place

EIGHTA verification walk

Forty minutes, in order, from a fresh world. Each step says what you should see. Keys are given for the default seed; if you are on another seed, use your own dictionary. Menu → New world with a blank seed box gives you a fresh emberglass only if you type it — otherwise you get a random one.

The opening On the woodpile where you wake, say Z T D M W. A large fire spreads through the pile and keeps going with your attention off it. A gold dot marks the cell holding the standing word. Ledger: ignition, spread, standing-word, residue.
The five ablations Drop W: fire, but nothing standing, and it dies when the fuel is gone. Drop T: cooler. Drop Z: one cell only. Drop M: nothing happens at all. Drop D: likewise. Minimum: D M.
The kiln Say T D M on the sconce beside the kiln door. Within a dozen ticks the door grinds back. Seals tab: "your key: 3 marks · 2 would have done it."
Reading Click the two inscriptions on the pit's east face, the ingots, the chalk ring's sign. Each goes from bright gold to dim on the map. Readings tab counts them.
The practice ring Burn something inside the chalk ring, then wait for dawn — tick 0 of any day. Everything inside comes back; anything you left standing in there does not.
Hardened ore Hold T D M on an ore lump until Inspect says "glowing through", then T G M. Ledger: quenched. Inspect calls it "harder than it was".
Frost Find the water standing in the sluice plug's crack. T G M to freeze it, then T D M to thaw it, and repeat. Each freeze takes a point out of three plug cells; five cycles opens it. Ledger: hard-water, split-by-cold, thaw. The pools then drain west.
Unmaking is refused Say B M at any ancient cell — a plug block, the vault seal, the built wall. "The stone does not admit it." Integrity does not move.
The cold pool Watch the deep pool on the terraces overnight. It skins over on its own, the ice comes out curved because the pool is a bowl, and around midday a bright spot appears on the stone under it. Ledger: gather, scorch. Nothing was said to make any of that happen.
Glass In the crucible ring, hold T D R until Inspect reads "the grains have stopped being grains", then T G R. Log: "It went hard all at once, and came out clear." The crucible seal opens. Do it again and let it cool by itself for the grey kind.
Steam On the enclosed water pocket against the vault's inner seal, hold C T D M. Pressure builds, the four walls lose integrity together, and after three bursts the seal goes. Ledger: steam, burst. Wait a minute and the pocket refills itself.
Light down a conduit At midday the shaft lights its own foot; the monument thirty cells west is unreadable. Fuse the sand drift along the hall floor to clear with a wide T Z D R then T Z U K G R, and light runs the length of it. Or burn the bones beside the monument instead. Ledger: light-through.
Root and patience With water in the channel, warm the root against the built wall with K D M — gently, it catches fire at 2.5 — then N M to hold the heat in it. Growth climbs to 3, then it bores. About two minutes of world time. Ledger: growth, root-split.
The water route With the plug and the wall both open, water runs from the terraces, down the swallow-hole, west along the channel, and into the cistern above the sealed chamber. Watch it arrive.
The finale Freeze the cistern water with T G J. Say E M and drag a bend across it. Hold it with N M. Take your attention away and wait for midday. Light goes down through the clear stone, gathers on the brazier four cells below, and it takes. The seal reads "opened by the world," because nothing was said.
The ending The last inscription is lit from below and reads back in your own words — whatever you called those four marks. Nothing else in the game does that.
Save Reload the page mid-run. Tick, world, dictionary, ledger, phrases, standing words and log all come back. Then Menu → audit: no dead ends found.

NINEYour seed's marks

This is the answer key. Every binding below is generated from the seed emberglass, which is the world you get on first load. Reading it ends the game as a game — it is here so a build can be verified in minutes rather than hours. A new seed rebinds all of it.

The eight radicals

Every mark is built from these, in fixed places on a 3×3 tile with a dot at the centre. Crack this and you can read a mark you have never seen.

Mark	Where it sits	Means
o	top left	heat
\	top middle	binding
c	top right	origin
n	left middle	flow
+	right middle	repetition
-	bottom left	negation
=	bottom middle	self-reference
i	bottom right	interiority

So o alone is to kindle, o with - is to quell, and o - = is that which is cold — heat, negated, made a thing. The subjects all carry =; the acts never do.

The twenty-four keys

Key	Kind	Is	Built from
Q	subject	ALL-WITHIN	self + interiority + repetition
W	qualifier	AGAIN	repetition + flow
E	act	SHAPE	binding + interiority
R	subject	SAND	self + repetition
T	qualifier	TWICE	repetition
Y	subject	THAT-WHICH-LIVES	self + origin + repetition
U	qualifier	NOT	negation
I	subject	THAT-WHICH-IS-COLD	self + heat + negation
A	qualifier	BEGINNING	origin
S	subject	WOOD	self + origin
D	act	KINDLE	heat
F	act	FLOW	flow
G	act	QUELL	heat + negation
H	qualifier	ENDING	origin + negation
J	subject	WATER	self + flow
K	qualifier	SLOWLY	flow + negation
Z	qualifier	OUTWARD	interiority + negation
X	subject	STONE	self + interiority
C	qualifier	WITHIN	interiority
V	act	GROW	origin + repetition
B	act	UNMAKE	binding + interiority + negation
N	act	BIND	binding
M	subject	THIS	self
,	act	LOOSE	binding + negation

The two inscriptions on the first wall

The opening: Z T D M W — outward, twice, kindle, this, again.
The last: A D I C — beginning, kindle, that-which-is-cold, within. A cold that burns.

The scholar's error

His second entry glosses the single mark on the sluice plug as water. It is N — BIND. He wrote water against it in four places and could not understand why the pools would not go down. Anyone who trusts him carries that mistake until they test it.

TENWhat is not proven

Mobile. Twenty-four letter keys and a drag camera assume a keyboard. The keys are clickable, so a tablet works, but no mobile layout exists.
The playtest gate. §16 of the spec: five naive players, each discovering ablation inside ten minutes, each naming a mark wrongly and correcting it themselves, each producing clear fused sand without being told such a thing exists. Not run. The third is the one that matters.
Fauna. Open question §15.1, still answered with zero. The world is live but nothing in it wants anything.
Long saves. Round-tripping is tested; a save that has been through hundreds of days of drift and scarring is not.

Deviations from the design spec, with reasons, are in NOTES.md beside the game file. The simulation lives between the CORE markers in Emberglass.html and touches no DOM, which is what makes all of the above checkable from a terminal.