The Book of Revelation structure

Thank you Yardstick for showing this structure. I can appreciate the amount of work that went into it. In my experience, the central theme is item number 4 that is the "Tribulation from perspective of earth looking up." Thus, it follows that the chiasmus is:

Revelation 1, what John saw.

    Revelation 2 & 3, the Church Age

        Rev 4-11, Tribulation from perspective of heaven looking down.

            Rev 12-16. Tribulation from perspective of earth looking up.

        Rev. 17&18, Destruction of Satan's empire.

    Rev. 19 & 20,  Lords return and reign

Rev. 21&22, The future.


From the chiasmus, as I understand it, the structure reads:
Tribulation from the perspective of earth looking up
Tribulation from perspective of heaven looking down and the Destruction of Satan's empire
the age of the church and the Lord's return and reign
What John saw and the future.

Thus, the central theme is a given and the parallels appear to be correct.