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This movie shows a square in a plane moving into the third dimension to
form a cube. The cube's shadow in the plane is added, and the square moves
again so that you can see how its shadow moves in the plane. The cube is
then removed and the viewpoint changes so that we look straight down on the
plane and see the movement again. The action now takes place entirely in
the plane, and you (or A. Square) must "imagine" the
threedimensional object that has this shadow.
This gives a depiction of the cube that is entirely twodimensional, so it
can be understood by the Flatlanders. It is imperfect, however, in that
the parts of the cube seem to lie ontop of itself in two dimensions (for
example, the red and blue squares overlap for a while) while we know this
is not what is happening in three dimensions.
