  Results from the most extensive study of the time-evolving dust structure
around the prototype "Pinwheel" nebula WR 104 are presented. Encompassing 11
epochs in three near-infrared filter bandpasses, a homogeneous imaging data set
spanning more than 6 years (or 10 orbits) is presented. Data were obtained from
the highly successful Keck Aperture Masking Experiment, which can recover high
fidelity images at extremely high angular resolutions, revealing the geometry
of the plume with unprecedented precision. Inferred properties for the
(unresolved) underlying binary and wind system are orbital period 241.5 +/- 0.5
days and angular outflow velocity of 0.28 +/- 0.02 mas/day. An optically thin
cavity of angular size 13.3 +/- 1.4 mas was found to lie between the central
binary and the onset of the spiral dust plume. Rotational motion of the wind
system induced by the binary orbit is found to have important ramifications:
entanglement of the winds results in strong shock activity far downstream from
the nose of the bowshock. The far greater fraction of the winds participating
in the collision may play a key role in gas compression and the nucleation of
dust at large radii from the central binary and shock stagnation point.
Investigation of the effects of radiative braking pointed towards significant
modifications of the simple hydrostatic colliding wind geometry, extending the
relevance of this phenomena to wider binary systems than previously considered.
Limits placed on the maximum allowed orbital eccentricity of e < 0.06 argue
strongly for a prehistory of tidal circularization in this system. Finally we
discuss the implications of Earth's polar (i < 16 deg) vantage point onto a
system likely to host supernova explosions at future epochs.
