tau brand¶
One mark for everything tau touches: the README, TauBar in the menu bar, the hub's screen, the necklace and the printed enclosures.
Idea¶
τ = 2π, one full turn. The ring is the full turn: tau is always on, always coming back around. Inside it sits a lower-case τ drawn from the same line weight. In the hero, the mark stands on the stage from the poster: two neon triangles, vertical beams and a reflecting floor.
Files¶
Every file is generated by render.py from one geometry, so the hero, icons and print files always agree. Edit render.py and run python3 docs/brand/render.py; don't edit the SVGs by hand.
| File | Use |
|---|---|
tau-hero.svg |
README and site hero, 1280×560. Animated; stops under reduced motion |
tau-mark.svg |
Neon mark on transparent. Dark backgrounds only, 48 px and up |
tau-app-icon.svg |
App icon tile (TauBar, hub screen, social). 32 px and up |
tau-mark-mono.svg |
One colour, filled. Engraving, embossing, stickers, 3D print. 24 px and up |
tau-coin.svg |
Solid disc with τ cut out. Favicon, menu bar template icon, pendant. Down to 16 px |
tau-wordmark.svg |
"tau" alone, one colour |
tau-lockup-dark.svg · tau-lockup-light.svg |
Mark + wordmark, for dark and light backgrounds |
tau-mark-mono.svg, tau-coin.svg and tau-wordmark.svg use currentColor: they render black as an <img> and take the text colour when inlined.
Colour¶
| Name | Hex | Use | |
|---|---|---|---|
 |
Void | #05071A |
Backgrounds |
 |
Signal | #FF2E63 |
Triangles, ring start, alerts |
 |
Ember | #FF7A3D |
Ring end, τ, beams |
 |
Flare | #FFB25C |
Highlights, the thinking arc |
 |
Core | #FFF4E0 |
Neon core, text on dark |
 |
Ink | #14060D |
One colour on light |
Neon (Signal → Ember ring, Ember τ with a Core line) only on Void or darker. On light backgrounds use Ink, flat.
Rules¶
- Clear space: keep one τ line width (the stroke) free on every side at minimum; twice that where you can.
- Don't stretch, rotate, outline, add drop shadows, recolour outside the palette, or put the neon mark on a light or busy background.
- Small sizes: below 24 px use the coin; below 48 px don't use the neon glow.
Motion¶
The hero's motion is the vocabulary for every screen tau has (hub display, TauBar, site):
- Breathing: the light inside the ring pulses slowly (5 s) when tau is idle.
- Thinking: a comet arc with a bright head circles the ring (7 s, eased) while tau works.
- Instrument rings: the dial ticks turn very slowly in opposite directions (80 s / 120 s).
Motion always stops under prefers-reduced-motion.
Terminal¶
The TUI (tau tui) draws the mark from the same geometry as render.py (the constants are
copied into tau_tui/brand.py), rasterised into half-block cells: each terminal cell holds two
square pixels (▀ with the top pixel as foreground and the bottom pixel as background), so a
24-column mark is 12 rows and the 16-column phone mark is 8 rows. It is anti-aliased toward Void,
uses the palette only (Signal → Ember ring, Ember τ with a Core centre line) and, following the
small-size rule, has no glow. Below 20 rows the mark gives way to the wordmark line. The header
τ carries the motion vocabulary in one cell: it breathes (Ember ↔ Flare, 5 s) while the welcome
card is on screen and runs the comet (Ember → Flare → Core, 2 s) while tau works; it is static
otherwise and under TEXTUAL_ANIMATIONS=none. Under TAU_TUI_ASCII=1 (terminals without the
block characters) the mark falls back to #, ^ and _ in Ember only and every box border is
drawn in ASCII.
State colours for terminal UIs (TauBar and the hub screen reuse them): ok / success = Flare,
error = Signal, rejected = Ember, running / pending = Core at 55 %, attention =
Flare, notice = Ember. There is no green and no red: shapes double the colours (●/○,
✓/✗, ◆).
Physical objects¶
For the necklace, enclosures and the hub's case, use tau-mark-mono.svg or tau-coin.svg. Both are one filled compound path with even-odd holes (no strokes), so CAD tools and slicers can import them, scale them and extrude them directly.
| At this mark diameter | Ring line | τ line |
|---|---|---|
| 20 mm | 1.1 mm | 1.3 mm |
| 30 mm | 1.7 mm | 2.0 mm |
| 40 mm | 2.3 mm | 2.6 mm |
- With a 0.4 mm FDM nozzle, keep lines at 1.2 mm or more: the ring mark from about 22 mm, the coin from about 18 mm.
- Raised or recessed by 0.6–1.0 mm reads well on enclosures. A two-colour print (Ink body, Ember inlay) matches the palette.
- The pendant loop (bail) is not part of the mark; add it in CAD above the ring.