# The soot field's calm lane (the FIRE_FIXTURE driver, like fire-heat):
# the brazier's plume rises on the heat channel's updraft. The manual
# 0.375 m/s breeze sits under the envelope's sheltering (wind_lay), so
# the column stands straight: the aloft mass drifts ~nothing, the
# column's top band climbs to the cap, and the field's total mass keeps
# growing (no decay - dilution only, and nothing vents the bounds this
# fast). Ends before the downwind orb ignites (frame 1611).
# frames: 1560
