The veil was a field of microscopic, umbrellalike aerostats programmed to 
fly in a sheet formation a few inches in front of Nell's face. The umbrellas 
were all pointed away
from her. Normally they were furled, which made them nearly invisible; they 
looked like the merest shadow before her face, though viewed sideways they 
created a subtle wall of shimmer in the air. At a command from Nell they would 
open to some degree. When fully open, they nearly touched each other. The 
outside-facing surfaces were reflective, the inner ones matte black, so Nell 
could see out as if she were looking through a piece of smoked glass. But 
others saw only the shimmering veil. The umbrellas could be programmed to 
dangle in different ways—always maintaining the same collective shape, 
like a fencing mask, or rippling like a sheet of fine silk, depending on the 
current mode.