Under proper conditions, lenticular sheets can
generate visual patterns which are usable as a
navigational aid. A distant observer can use this
navigational aid to precisely determine its relative
position.

The navigational aid is constructed by mounting a
lenticular sheet over a pattern of periodically
spaced lines sharing the sheets period. This
configuration results in the appearance of lines
perpendicular to the original pattern,
which are visible to a distant observer. The
apparent location of these lines depends on the
position of the observer relative to the
navigational...