Question

What is a non-polygon?

Answer 1

Non-polygon is a geometric object that does not conform the definition of polygon (see below).

Explanation:

Polygon is a geometric object that consists of certain finite number of segments (let's label them `s_1`, `s_2`,..., `s_N`) that satisfy the following conditions:

(a) they are sequentially connected into a closed figure, that is the end of `s_1` coincides with the beginning of `s_2`, end of `s_2` coincides with beginning of `s_3` etc... end of `s_(N-1)` coincides with beginning of `s_N` and end of `s_N` coincides with beginning of `s_1`;

(b) all the points of coincidence mentioned above are different;

(c) there are no other intersection points among these segments.

In addition: Note that polygons are two-dimensional, (planar) and that the segments are straight lines, so any shape which includes an arc is not a polygon. (A circle is therefore not a polygon).

A geometric object that does not satisfy one or more of these three conditions IS NOT a polygon and you can name it a non-polygon.