I am German, and we have have a completely different comma system. Due to various reference on this great site here, I bought The Penguin Guide to Punctuation and worked through the comma section. What can I say, I'm shocked about my lack of knowledge, although the comma rules in English are far more easier than in German. I instantly took one of my books and verified correct commas there.
There was one sentence, which I believe was incorrectly punctuated:
Memory can be implemented by delays, and wiring by various walls to guide the one extra bit per site needed to represent the walls.
In my opinion a gapping comma is missing, because the phrase can be implemented was left out in the second part. Therefore, I would add a comma
Memory can be implemented by delays, and wiring, by various walls to guide the one extra bit per site needed to represent the walls.
Now we have to commas. The first one joins the two complete sentences, and the second one marks that between wiring and by various a phrase is missing.
Can someone tell me whether I'm wrong here?