A stack of identical polygons will make a prism.A stack of polygons which gradually become smaller will make a pyramidal frustum.
If the stack continues until the polygon becomes infinitesimally small, then they will make a pyramid.
Under the same conditions, discs will make a cylinder, conic frustum and cone, respectively.
Since any polygon can be constructed from a combination of other polygons, I would call this rule a "trivial property of polygons".
pyramid (not including the vertex) Prism
A polygon is pretty much any enclosed shape constructed of straight line segments connected end to end. The angles do not have to be right. In fact, they usually aren't. A right angle would NEVER be a polygon, as it is just one right angle. In Euclidean geometry a right angle must be accompanied by two acute angles to form a triangle--the polygon with the smallest number of sides.
The definition of a irregular polygon is any polygon that is not a regular polygon.
A polygon is a Two dimensional figure that is closed.
a cone (not including the vertex) and a cylinder
The constructed polygon name for a 24-sided regular polygon is an icosikaitetragon.
Since any polygon can be constructed from a combination of other polygons, I would call this rule a "trivial property of polygons".
A diamond is indeed a polygon. It's a closed figure lying on a plane and constructed of straight lines.
This is called a frequency polygon.
More complicated polygons.
A Zamboni pile is an early electric battery constructed from discs of silver foil, zinc, foil and paper.
An equilateral triangle, a square and a hexagon.
A bell is a shape, but not a polygon. Polygons are constructed only from straight line segments, they do not contain curves (a circle is not a polygon either, unless you imagine it as being composed of infinitely many line segments, each of which is infinitely short).
Any 5 sided shape constructed from straight non overlapping lines. A 5 sided polygon.
pyramid (not including the vertex) Prism
Cone ( not including the vertex ) Cylinder ( APEX )