Pentagons

Considering now polygons with 5 edges (pentagons), we observe that the new pentagons do not necessarily look the same as the initial pentagon. However, unlike what happened with quadrilaterals, and similarly to what happened with triangles, the new pentagons appear to be arbitrary with no particular characteristics.

In fact, any pentagon can be the result of the bisection iterative process; also in this case the choice of the initial pentagon determines univocally the sequence of pentagons. This case is similar to the case of triangles, except that the new polygons are not necessarily similar to each other.

It should be also noted that the pentagons seem to appear alternately with the same shape but with decreasing size.

Why is that so?