Nobody. Understands. Punctuation.

I am more than happy to truly believe this premise (and if you read some of the things I write, and how I use punctuation, I hope the reader will agree ;P), and can come up with situations where the extra comma "breaks the rythm" and cases where it "makes the sentence".

> Momentum, syncopation, rhythm and pattern make a sentence flow, because writers are trying to transfer the voices in their heads into yours.

However, I simply can't bring myself to read this without speaking "rythm, and pattern": the sentence is expertly crafted and frankly sounds amazing; but, if I accept the author's premise that he really and truly carefully decided to not put a comma there because he didnt want me to pause, the sentence sounds horrible: in fact, this sentence sounds pretty un-lyrical to me unless I also add a pause--yes, not one but two added commas--after "pattern", at which point I would say it sounds downright powerful; I could, alternatively, appreciate a smaller pause between "momentum" and "syncopation", which would form a grouping that I think almost sounds even better? (though which I have a difficult time "performing"), but then we have to give up the first comma as well: "momentum/syncopation, rythm and pattern, are"... I really would love to hear the author read this sentence of the article out loud.

"and parentheses" what? And they are also like em dashes?

Edit: Thank you for the explanation folks. For whatever reason I found the use of commas to denote the aside very difficult to parse. I think maybe it's because of the first comma after "In this case."

> In this case, em dashes are doing something similar to a pair of commas (which can also denote side info but they do it more casually) and parentheses.

The commas after "pair of commas" are the parenthetical commas he is describing