To give an example,
is a collection of 6 points
in the plane. The order in which the points are
taken is important.
This ordering is cyclic, in
that 1 comes before 2 and after 6.
The blue lines are not part of the hexagon. They
are just drawn in to indicate the ordering of
the points. They represent a circuit you would
take if you walked from point to point in the
The hexagon with the red dot in the center
is convex ,
The others are not.
An octagon is
just like a hexagon, except that
there are 8 points. In general, a
N-gon is a collection of N points in the plane,
ordered as above. The words
N-gon and polygon