The patent whose illustration I reproduced here the other day is a weird one; I can't take away from that. But in many respects, it's a well-written and reasonable patent, and the way the law is written, I don't see any reason why it shouldn't have been granted.
Some of the key things a patent should show are novelty, disclosure of the best mode of carrying out the invention, and comparison with the prior art. Now, I haven't carried out an exhaustive survey of the butt-kicking literature, but the inventor seems to have taken some time to do all of these. You can contrast that with some of the loser patents that are being granted in what are supposedly more exalted fields. For example, pharmaceuticals. . .
Take a look at those requirements again. Novelty is the easy one, in some ways. These days, you just go on for a paragraph or two about how unprecedented your invention is, contrasting it with the most hapless previous examples you can come up with. Best mode disclosure is a bit more tricky. There's a legal quagmire between this requirement and your right to keep a trade secret, and some truly nasty patent battles have been fought in that swamp. Most of the time, though, you can disclose best mode without too much problem, since the process is still being refined as you write the patent. This lets you show the best way you currently know how to do things, and allows you to reserve later tricky refinements as trade secrets. (When it gets nasty is when there's evidence that these two eras overlapped.)
That brings us to prior art, and here's where the stink of dead fish becomes pronounced. As Greg Aharonian never ceases to point out, technology patents in general do an awful job disclosing prior art. In some cases, the reason for this is pure laziness or stupidity. More oftenm though, the motives are baser. If you just ignore prior art that might invalidate your patent, you can get the thing granted more easily. Then it's an uphill fight for someone who wants to invalidate it - after all, you've got the law on your side until someone proves otherwise. It's doable, but you've raised a barrier that someone will have to think about.
In recent years, there's been a variation on this technique. There are patents that actually disclose what, to an outside observer, would appear to be invalidating prior art - and the patent office grants the thing anyway. This disclosure usually consists of dropping the references into a list, and not dwelling on them in the text. The patent examiners are so overworked that they let a lot of this stuff through.
And if you want to invalidate one of these winners, good luck. Because now the very thing you want to use to show the patent shouldn't have been granted is. . .in the patent. And, legally, has been assumed to have been considered, and found insufficient to deny the application. You're stuck with arguing that the examiner made a mistake, which is generally a losing position.
You've got a better chance of getting one of these through if your examiner is not only overworked, but incompetent. I have it on good authority that some companies will submit the identical application in multiple copies (which is illegal,) waiting to see which examiners get assigned to the cases. Then they'll pick the one that they know from experience is the least demanding or skillful, and withdraw the other applications. I'm proud to say that that one wouldn't have occurred to me.