Sense of Direction — fly body model provenance
==============================================

Served at https://joestart.com/fly/models/NOTICE.txt and linked from /fly/about twice:
from the "the fly's body and gait" row of the caveat table, and from the credit section
at the foot of that page.


WHAT THIS DIRECTORY CONTAINS
----------------------------

Nothing but this notice and a copy of the Apache License 2.0.

There is no model file here, and that is deliberate. The fly in the studio is built
from primitives in `scene/fly.ts`. No mesh is downloaded at runtime and no third-party
geometry is distributed by this site.


WHY THE ATTRIBUTION IS HERE ANYWAY
----------------------------------

The fly's proportions are not invented. Every dimension of the animal — the origin of
every body segment, the length of every limb link, the radius of every collision
primitive, and the colour of every material — was measured from:

    flybody/fruitfly/assets/fruitfly.xml
    https://raw.githubusercontent.com/TuragaLab/flybody/main/flybody/fruitfly/assets/fruitfly.xml
    sha256 d14946fd0311025ecca70c8eeb5de80e1fe18700d3072be37ecbb18d33d80fd8
    65,787 bytes, fetched 2026-09-15

That file is the MuJoCo MJCF of the flybody model: the same file that defines the
animal flybody's physics simulation actually walks. Its collision geometry is already
a set of ellipsoids, capsules and cylinders with measured semi-axes, and those are the
numbers used. The full table, with the provenance of each one and an explicit mark
against the handful that are free parameters rather than measurements, is in
`scene/proportions.ts` in this site's source.

Deriving proportions from an Apache-2.0 work does not obviously require a notice. It is
given regardless, because the honest description of this fly is "flybody's proportions,
our triangles", and half of that sentence is someone else's work.


ATTRIBUTION
-----------

Fly body proportions from flybody (Google DeepMind / HHMI Janelia Research Campus),
used under the Apache License 2.0.

  Vaxenburg R, Siwanowicz I, Merel J, Robie AA, Morrow C, Novati G, Stefanidi Z,
  Both G-J, Card GM, Reiser MB, Botvinick MM, Branson KM, Tassa Y, Turaga SC.
  Whole-body physics simulation of fruit fly locomotion.
  Nature 643:1312-1320 (2025). doi:10.1038/s41586-025-09029-4

  Source:  https://github.com/TuragaLab/flybody
  Licence: Apache License 2.0 — full text in LICENSE-Apache-2.0.txt beside this file,
           and at https://www.apache.org/licenses/LICENSE-2.0

The upstream repository has no NOTICE file and its LICENSE appendix copyright line is
the unfilled Apache boilerplate, so there is no canonical one-line copyright string to
reproduce. The block above is what satisfies §4 in its absence, and it matches the
citation flybody's own README asks for.


WHAT IS NOT A CLAIM
-------------------

The beret is not a claim. It has no counterpart in flybody, in the connectome, or in
any fly. It carries no number and reads out nothing.

The walk is animated, not simulated. Step frequency and body heading are computed from
the pen's speed and direction; no motor neurons are modelled anywhere in this project,
and flybody's locomotion controllers are not used. The only physiology in the gait is
the clamp on step frequency (5-16 Hz) and duty factor (0.65 falling to 0.5), applied as
a rule from published walking measurements.