For example, if an object has a top view with 180' symmetry, then any front and back views are identical. This helps to get an all- around feeling for the sculpture. In Figure 20 is the top view of the Robert Longhurst sculpture Arabesque XXIX . Since the top view has 180 o symmetry, the view from the opposite side will be the same. Figure 19 Figure 20.
Knots frequently have symmetries from different viewpoints.
These symmetries help to hypersee the knot. David Finn, As The Eye Moves, Harry Abrams, New York, 1968. In Modern Art, Princeton University Press, 1983. On Sculpture, Macdonald, 1966.