What is that?

“The Octagon,” they say

Egyptian defensive site,

Like a “Pentagon” in a way,

Except with three more sides basically,

And then we agree,

On the topic of Egypt verily,

Is the Tel formally,

Of how many layers of civilization

Are around

So we say about a Pentagon we found

The Tel over the years

Until 500 are there

501 Pentagons,

You understand

500 levels below again,

What is below the Octagon then?