docs: a branding folder, and the three marks are not interchangeable

Shift is the logo, Guru is the icon, SchCotie is the mascot, and the difference
between them is not stylistic. An icon works once, at one size, in one state. A
mascot has to be able to *do* things -- confused, pleased, asleep, seen from
behind -- which is why it costs more and is drawn last. Written down because
this is exactly the kind of decision that gets re-derived badly.

Assets/ becomes docs/branding/, which also fixes two things:

  * Filenames had spaces in them, so every reference needed quoting. They are
    lowercase and hyphenated now.
  * Assets/ held hand-written SVG and generated PNG in one directory, which is
    the one rule docs/guides/layout.md states.

The guide records what was previously only in people's heads:

  * The constraint everything answers to -- include/logo.h is a 128x128
    single-channel coverage mask, so a mark has to survive as a solid shape in
    one colour and be recognisable at 24 px. Colour is the last decision, never
    the first.
  * Guru's purple is load-bearing. PSOGM_BG #4B1D9A is deliberately not the
    accent #7C5CFF, and theme.h's rule is that the full-bleed purple belongs
    entirely to failure. If Guru appears in accent violet on a sticker, the deep
    purple stops meaning "the machine stopped" -- and it is the only colour in
    the system that means anything.
  * Why shift-mask.svg is a separate file from shift.svg. mklogo.py reads ink as
    (255 - luminance) * alpha, so tones survive as coverage and the relationship
    inverts: darkest here is brightest on screen. Copying the violet fills would
    light the object from below.
  * Why a raster is committed beside its SVG. inkscape is not a build
    prerequisite, so requiring a vector rasteriser would break the build on most
    hosts for a file that changes about once a year.
  * That the BSD daemon is copyrighted and SchCotie must be drawn from the
    concept rather than from Beastie. A daemon is a Greek daimon and a Unix
    background process; neither is ownable. The pitchfork, the sneakers and that
    face are.

Format rule: SVG, or PNG at high resolution with no lossy compression, nothing
else. SVG is the source of truth for every mark and a raster is generated from
it, never edited.

include/logo.h regenerates byte-identical from the new path -- only the source
comment differs. The two old wordmark SVGs were deleted outside this session and
are left deleted; their PNGs are kept as superseded-*.png for reference.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VQ7Qx8E1q1M1bbCq8QLHS2

docs/README.md

@@ -10,8 +10,10 @@ different questions and go stale at four different rates.
 | **[guides/](guides/)** | *How to work on it* | Imperative. Build it, test it, add to it. |
 | **[history/](history/)** | *Why it is the way it is* | Past tense. Bugs whose cause is not visible from the fix. |
 
-Plus one rule that belongs to no category and applies to everything:
-**[licensing.md](licensing.md)** — read it before copying anyone else's code in.
+Plus two that belong to no category and apply to everything:
+**[licensing.md](licensing.md)** — read it before copying anyone else's code in —
+and **[branding/](branding/)**, which holds the marks and the rules for using
+them.
 
 ---
 
@@ -98,6 +100,12 @@ good chance it is in there.
 | [layout.md](guides/layout.md) | Repository map, and how to add a program or a port. |
 | [adding-a-driver.md](guides/adding-a-driver.md) | Writing one, binding it, publishing its class vtable. |
 
+## branding/ — the marks
+
+| | |
+|---|---|
+| [README](branding/README.md) | Shift the logo, Guru the icon, SchCotie the mascot: what each is for, the colour rule, and why a raster is committed next to its SVG. |
+
 ## history/ — why it is the way it is
 
 | | |

docs/branding/README.md

@@ -0,0 +1,179 @@
+# Branding
+
+Three marks, three different jobs. They are not interchangeable and the
+difference is not stylistic.
+
+| | | |
+|---|---|---|
+| **Shift** | *the logo* | An abstract mark. Non-human, non-animal. Signs the system. |
+| **Guru** | *the icon* | A pictogram. Denotes one state. Has a face; has no body. |
+| **SchCotie** | *the mascot* | A character. Has a body, poses and expressions. |
+
+The distinction that decides everything else: **a mascot has to be able to
+do things.** An icon works once, at one size, in one state. A character has to
+work confused, pleased, asleep and from behind — which is why it costs more and
+why it is drawn last.
+
+---
+
+## The one constraint everything answers to
+
+**The kernel draws its mark as a 128×128 single-channel coverage mask.**
+`include/logo.h` holds no colour at all — two pixels per byte, sixteen levels of
+ink — and the kernel composites it in whatever `include/theme.h` says.
+
+So any mark that will end up there has to survive as **a solid shape in one
+colour at 128 px, and be recognisable at 24**. That rules out hairlines, thin
+rings and anything that depends on a gradient to read. The mark this replaced
+failed on all three counts.
+
+Colour is therefore the *last* decision, never the first. Design the silhouette,
+then colour it.
+
+---
+
+## Shift — the logo
+
+`shift.svg`
+
+Three slabs, displaced: the layer diagram in
+[../architecture/README.md](../architecture/README.md) as a solid object, and
+the kernel's name (**SchIFT**) as a shape.
+
+- **Any colour.** This is a fact about the pipeline, not a preference — the
+  coverage mask carries none, so the loader draws it in metal and the kernel in
+  the theme accent, from the same bytes.
+- **With or without a wordmark.** Set "SchOS" beside it in **Roboto Bold**,
+  which is already in the tree (`ports/Roboto`), already Apache-2.0, and already
+  in `NOTICE`.
+- Non-human and non-animal, permanently. The character work belongs to
+  SchCotie; a logo that starts growing a face has taken the mascot's job.
+
+## Guru — the icon
+
+`guru.svg`
+
+The crash face. Mythic rather than cartoon — closer to a temple carving than a
+character — square or nearly so, with an expression that stays in the
+`:(` / `:|` register.
+
+**Purple, and only purple, and only here.** `theme.h` states the rule it
+enforces:
+
+> normal states are calm and dark; only failure is loud. PSOGM keeps the
+> full-bleed purple entirely to itself, which is what makes it mean something.
+
+That purple is `PSOGM_BG #4B1D9A`, and it is deliberately **not** the accent
+`#7C5CFF`. If Guru ever appears in accent violet on a splash, a sticker or a
+README header, the deep purple stops meaning *the machine stopped* — and it is
+the only colour in the system that means anything at all.
+
+So: Guru does not leave the crash screen.
+
+## SchCotie — the mascot
+
+*Not drawn yet.*
+
+A daemon: **the process that works while nobody is watching.** The horns are a
+pun on the word; the meaning is the background job that keeps running after you
+have walked away — which is `schinit` supervising, restarting what dies, awake
+at 3am. Patient and watchful rather than mischievous.
+
+Horns carry **X** — POSIX, Unix, X11 — one substitution reading three ways.
+
+Two constraints that follow from the section above. A thin X is two diagonal
+strokes and dissolves at small sizes, so it wants to be **solid wedges with the
+X notched out as negative space**: the horn silhouette survives downscaling and
+the X appears as you get closer. And it needs a **turnaround** — front, side,
+three-quarter, matching heights on shared construction lines — because a
+character drawn once at one angle only ever works at that angle.
+
+### The licensing point, which is not optional here
+
+**The BSD daemon is copyrighted.** Marshall Kirk McKusick holds it and the terms
+are not a free licence. A character that reads as "Beastie, but purple, with X
+horns" is a derivative-work argument, and this mark would be in every image
+SchOS ships, beside a `NOTICE` file this project has been careful about.
+
+The concept is not the problem. A daemon is a Greek *daimon* and a Unix
+background process — neither is ownable. What belongs to Beastie is the
+execution: the pitchfork, the sneakers, that red, that face, that pose. Horns, a
+tail and a small imp are generic and thousands of years old.
+
+**Draw from the idea. Do not have a picture of Beastie open while you do it.**
+
+---
+
+## Colour
+
+From `include/theme.h`, which is the source of truth. Nothing here restates a
+value it does not already define.
+
+| | | |
+|---|---|---|
+| `SCH_BG` | `#0C0E13` | Ground. Near-black with a blue cast, because pure black reads as "switched off". |
+| `SCH_FG` | `#E6E8EC` | Primary text |
+| `SCH_DIM` | `#707784` | Secondary |
+| `SCH_ACCENT` | `#7C5CFF` | The one accent. Shift, SchCotie, anything calm. |
+| `PSOGM_BG` | `#4B1D9A` | **Failure only.** Guru's ground and nothing else's. |
+
+## File formats
+
+**SVG, or PNG at high resolution with no lossy compression.** Nothing else.
+
+No JPEG anywhere — a mark is flat colour with hard edges, which is the exact
+case JPEG is worst at, and the ringing it leaves around an edge is permanent.
+No screenshots of marks. No re-exports of re-exports: go back to the SVG.
+
+**SVG is the source of truth for every mark.** A raster is something generated
+from it, never edited.
+
+## What is in here, and why a raster is committed
+
+```
+shift.svg               the logo, in colour
+shift-mask.svg          the same geometry in greys -- see below
+shift-mask.png          rasterised from it, committed on purpose
+uberblock.svg           SchFS
+guru.svg                the crash icon
+superseded-*.png        the old wordmark, kept for reference only
+```
+
+The pipeline is three stages:
+
+```
+shift-mask.svg  --(inkscape)-->  shift-mask.png  --(make logo)-->  include/logo.h
+```
+
+**Both intermediates are committed, and that is deliberate.** `inkscape` is not
+a build prerequisite — see [../guides/building.md](../guides/building.md) — so a
+build that required a vector rasteriser would stop working on most hosts for the
+sake of a file that changes about once a year. The PNG is regenerated by hand
+when the SVG changes, and `make logo` turns it into the header.
+
+### Why the mask is a separate file from the logo
+
+`tools/python/mklogo.py` reads ink as `(255 - luminance) * alpha`, so **tones
+survive as coverage** rather than being flattened — and the relationship
+inverts: *darkest here is brightest on screen*. Copying the violet fills from
+`shift.svg` would light the object from below.
+
+So `shift-mask.svg` is the same geometry in greys chosen for how the mask reads.
+Two files sharing one geometry is a drift hazard; the `<desc>` in both says so.
+If either is edited, edit both.
+
+---
+
+## What this does not cover
+
+- **No trademark position.** These are marks the project uses, not marks anyone
+  has registered or defended.
+- **No usage rules for third parties** — nothing says what someone else may do
+  with them. Worth writing before anything is published.
+- **SchCotie does not exist.** Everything above it is a brief, not a
+  description.
+- **Guru is drawn but not wired in.** `panic.c` still renders `:(` from
+  primitives, and there is a real argument for keeping it — see the note in that
+  file about being "legible as a mood without being a picture of anything".
+- **No wordmark lockup is specified.** "Roboto Bold beside it" is not a spacing
+  rule, a size ratio or a clear-space margin, and it will want to be.

docs/branding/guru.svg

@@ -0,0 +1,12 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 200 200" width="200" height="200">
+  <title>Guru — the PSOGM face</title>
+  <desc>The crash-screen face. Chamfered corners quote the old SchOS letterforms.
+  Drawn here for reference only: kernel/core/panic.c builds it from primitives
+  rather than from a bitmap, so it scales with the display and costs nothing in
+  the kernel image.</desc>
+
+  <path fill="#7C5CFF" d="M58 24 L142 24 L176 58 L176 142 L142 176 L58 176 L24 142 L24 58 Z"/>
+  <path fill="#2B0F52" d="M74 82 h16 v22 h-16 Z"/>
+  <path fill="#2B0F52" d="M110 82 h16 v22 h-16 Z"/>
+  <path fill="#2B0F52" d="M72 128 h56 v11 h-56 Z"/>
+</svg>

docs/branding/shift-mask.svg

@@ -0,0 +1,29 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 200 200" width="200" height="200">
+  <title>SchOS — Shift, as an ink mask</title>
+  <desc>SAME GEOMETRY AS "shift.svg". Only the fills differ, and they are
+  greys because they are not colours: tools/python/mklogo.py reads ink as
+  (255 - luminance) * alpha, so what is stored is coverage. The kernel then
+  composites that coverage in whatever include/theme.h says the accent is.
+
+  The greys run DARK AT THE TOP because the relationship inverts: darkest here
+  is most ink, which the kernel draws brightest. Copying the violet fills from
+  the colour mark would light the object from below.
+
+  Two files with one geometry is a thing that can drift. If either is edited,
+  edit both -- or replace this pair with one file and regenerate the other.</desc>
+
+  <!-- bottom slab: least ink, so the kernel draws it dimmest -->
+  <path fill="#6E6E6E" d="M54 126 L158 126 L128 156 L24 156 Z"/>
+  <path fill="#888888" d="M24 156 L128 156 L128 167 L24 167 Z"/>
+  <path fill="#949494" d="M158 126 L158 137 L128 167 L128 156 Z"/>
+
+  <!-- middle -->
+  <path fill="#3A3A3A" d="M72 84 L176 84 L146 114 L42 114 Z"/>
+  <path fill="#5C5C5C" d="M42 114 L146 114 L146 125 L42 125 Z"/>
+  <path fill="#6A6A6A" d="M176 84 L176 95 L146 125 L146 114 Z"/>
+
+  <!-- top slab: most ink, so the kernel draws it brightest -->
+  <path fill="#0B0B0B" d="M90 42 L194 42 L164 72 L60 72 Z"/>
+  <path fill="#2A2A2A" d="M60 72 L164 72 L164 83 L60 83 Z"/>
+  <path fill="#3A3A3A" d="M194 42 L194 53 L164 83 L164 72 Z"/>
+</svg>

docs/branding/shift.svg

@@ -0,0 +1,27 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 200 200" width="200" height="200">
+  <title>SchOS — Shift</title>
+  <desc>Three slabs, displaced. The layer diagram in docs/architecture/README.md
+  as a solid object, and the kernel's name (SchIFT) as a shape.
+
+  Each slab shows three faces: the top, the front edge under its lower side, and
+  the right-end wall under its right diagonal. The right wall is not optional --
+  without it the slab has no thickness where it is widest, and the corner reads
+  as a hole rather than an edge.
+
+  Geometry is shared with "shift-mask.svg"; see that file.</desc>
+
+  <!-- bottom slab -->
+  <path fill="#3C2E85" d="M54 126 L158 126 L128 156 L24 156 Z"/>
+  <path fill="#31256E" d="M24 156 L128 156 L128 167 L24 167 Z"/>
+  <path fill="#291F5C" d="M158 126 L158 137 L128 167 L128 156 Z"/>
+
+  <!-- middle slab -->
+  <path fill="#5B44C4" d="M72 84 L176 84 L146 114 L42 114 Z"/>
+  <path fill="#4B37A6" d="M42 114 L146 114 L146 125 L42 125 Z"/>
+  <path fill="#3F2D8C" d="M176 84 L176 95 L146 125 L146 114 Z"/>
+
+  <!-- top slab -->
+  <path fill="#7C5CFF" d="M90 42 L194 42 L164 72 L60 72 Z"/>
+  <path fill="#6949E0" d="M60 72 L164 72 L164 83 L60 83 Z"/>
+  <path fill="#5B3FC9" d="M194 42 L194 53 L164 83 L164 72 Z"/>
+</svg>

docs/branding/uberblock.svg

@@ -0,0 +1,44 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 200 200" width="200" height="200">
+  <title>SchFS — Uberblock</title>
+  <desc>The uberblock ring: slots written round-robin, one of them newest.
+  Mount takes the highest-numbered slot that validates, which is the whole
+  consistency argument for the format.
+
+  Every slot is an explicit annular sector. An earlier version drew them with
+  stroke-dasharray on a circle, which is shorter to write and wrong in two ways:
+  a dash centred on the path start straddles the closure and renders as TWO
+  pieces with a seam between them, and the normal slot underneath the marked one
+  still drew, showing through. Neither can happen here -- the marked slot is one
+  shape and the slot it replaces is simply not emitted.
+
+  12 slots at 20 degrees of ink and 10 of gap, which closes at 360 exactly. The
+  marked slot is index 1, counting clockwise from the top.
+
+  It is marked twice over: it carries the accent, the same colour as the root at
+  the centre, and it reaches outward past the ring while sharing the inner edge
+  with every other slot. The colour is the reading on screen; the size is what
+  survives include/logo.h, which is a single coverage channel and keeps no
+  colour at all.
+
+  Stands alone, with no reference to SchOS, as projects/schfs-linux/README.md
+  requires.</desc>
+
+  <g fill="#3C2E85">
+    <path d="M85.93 20.23 A81.00 81.00 0 0 1 114.07 20.23 L110.25 41.90 A59.00 59.00 0 0 0 89.75 41.90 Z"/>
+    <path d="M162.05 47.93 A81.00 81.00 0 0 1 176.12 72.30 L155.44 79.82 A59.00 59.00 0 0 0 145.20 62.08 Z"/>
+    <path d="M179.77 85.93 A81.00 81.00 0 0 1 179.77 114.07 L158.10 110.25 A59.00 59.00 0 0 0 158.10 89.75 Z"/>
+    <path d="M176.12 127.70 A81.00 81.00 0 0 1 162.05 152.07 L145.20 137.92 A59.00 59.00 0 0 0 155.44 120.18 Z"/>
+    <path d="M152.07 162.05 A81.00 81.00 0 0 1 127.70 176.12 L120.18 155.44 A59.00 59.00 0 0 0 137.92 145.20 Z"/>
+    <path d="M114.07 179.77 A81.00 81.00 0 0 1 85.93 179.77 L89.75 158.10 A59.00 59.00 0 0 0 110.25 158.10 Z"/>
+    <path d="M72.30 176.12 A81.00 81.00 0 0 1 47.93 162.05 L62.08 145.20 A59.00 59.00 0 0 0 79.82 155.44 Z"/>
+    <path d="M37.95 152.07 A81.00 81.00 0 0 1 23.88 127.70 L44.56 120.18 A59.00 59.00 0 0 0 54.80 137.92 Z"/>
+    <path d="M20.23 114.07 A81.00 81.00 0 0 1 20.23 85.93 L41.90 89.75 A59.00 59.00 0 0 0 41.90 110.25 Z"/>
+    <path d="M23.88 72.30 A81.00 81.00 0 0 1 37.95 47.93 L54.80 62.08 A59.00 59.00 0 0 0 44.56 79.82 Z"/>
+    <path d="M47.93 37.95 A81.00 81.00 0 0 1 72.30 23.88 L79.82 44.56 A59.00 59.00 0 0 0 62.08 54.80 Z"/>
+  </g>
+
+  <g fill="#7C5CFF">
+    <path d="M132.15 11.67 A94.00 94.00 0 0 1 160.42 27.99 L137.92 54.80 A59.00 59.00 0 0 0 120.18 44.56 Z"/>
+    <circle cx="100" cy="100" r="20"/>
+  </g>
+</svg>