[AndrewC]

it's whether a useful circuit can be designed by an evolutionary process

Well, it may be to you, but here we are discussing a specific circuit. Since you have a background in the subject, you might have some opinion as to the evolved circuit and how it functions. Specifically, how it functions compared to the patented circuit in the environment and uses for which it was designed.

[null and void]

Nope. I've done a total of about 30 hours of electronics engineering in the last 30 years. (Shoulda studied ME) My education/experience is so stale, my inputs would be suspect.