Harry's Guardian angel

[Curly]

Why don't we simply take all the characters and see if it's possible that they did it?

Arbitrarily starting with Cowl :

M.O.
 He would have no problem getting into the apartment, could well have Harry under surveillance, would have control over Bob not, just telling him to sleep and forget he was there but also possibly asking him for help to fix the tool he helped create.

Motive, Cowl's motives are shrouded in mystery, so we don't necessarily know whether he is with, against or indifferent to Harry.

Miscellaneous: Cowl knows that Harry has Bob elsewhere in the books,

[neurovore]

Why don't we simply take all the characters and see if it's possible that they did it?

Because we will end up with even more possibles and no way of ruling out any of them ?

[Curly]

Because we will end up with even more possibles and no way of ruling out any of them ?

So?

We can't rule out anything until the books explicitly tell us what's going on, so we might as well do it thoroughly, at least it's something to do while we wait for Changes.

It's not like we'll get a prize for having said the right thing no matter how much we just knew it.

[neurovore]

So?
We can't rule out anything until the books explicitly tell us what's going on,

I think there are other modes of logic that are more helpful that going through the entire cast in order, though.

It's not like we'll get a prize for having said the right thing no matter how much we just knew it.

Well, it certainly gives me a warm glow of satisfaction to be proven right...

[Curly]

I think there are other modes of logic that are more helpful that going through the entire cast in order, though.

Such as? I like to have things out-there in a nice orderly way, plus debating how some minor character would cope with the challenge would be interesting and almost, but not quite that thing Jim is supposed to frown upon.

Well, it certainly gives me a warm glow of satisfaction to be proven right...

It usually grants me a feeling of satiety, but not when I've essentially picked one choice out of a handful.

[Hoohaw]

Why don't we simply take all the characters and see if it's possible that they did it?

Cool...how about...erh....Sanya?   

[SmartAlec]

We can certainly narrow it down.

- Knowledge. Whoever did it knew about Harry's lab, knew about Little Chicago, and has enough understanding of the theory and construction of the table, to spot a mistake in the table's construction and correct it.

- Opportunity. This person or persons would then have had to get past Harry's defences, wards and steel door without leaving a trace of their entry, during the couple of days or so between Harry's first and second attempts at using Little Chicago.

- Motive. That person or persons would need to have a reason for doing so; fixing Little Chcago is an act that both saves Harry's life and leaves him with a fully operational scrying table. Whoever did it would need to want that state of affairs to be so.

We can also compare this act to the way the characters have acted in the past, to see if it fits any established patterns of behaviour.

For example:

Rashid, the Gatekeeper

Knowledge: Possible. The Gatekeeper seems privy to future events; he may know of a possible future in which Little Chicago malfunctions.

Opportunity: I'm unsure to what extent the Gatekeeper's powers run; he may be mighty enough to enter Harry's apartment directly, foil whatever defences protect it, and be able to repair Little Chicago whilst hampered by the apartment's threshold.

Motive: Tricky. He seems a benevolent man, concerning Harry at least. However, taking it upon himself to avert a future in which Harry is killed using Little Chicago sounds like exactly the kind of paradox-causing event that Bob describes as bad news. How far would the Gatekeeper be willing to go?

MO: Doesn't quite fit. Previous actions by the Gatekeeper have either been passive (waiting for certain events to occur) or have been done so openly (meeting Harry in Summer Knight; sending a note in Proven Guilty). Why not simply add that the table is flawed, in his note? Or, send another one?

Lasciel's Shadow

Knowledge: Yes. She has been in Harry's head all throughout the construction of Little Chicago, and has powers of comprehension greater than Harry's.

Opportunity: Being right there when the scale model is used could potentially allow her to aid Harry during the spellcasting. See MO.

Motive: Clear. If Harry dies, he cannot be tempted to pick up the coin, and the Shadow ceases to exist. She would want to prevent that.

MO: Familiar. Lash has given aid unasked in the past, including spellcasting aid. She claimed that in order to protect Harry during the use of Little Chicago, he would need to pick up the coin; however, this may have been a lie in order to get him to do so. Having lied about it, Lash cannot then admit the truth without exposing her lie and weakening all claims she makes in the future that Harry needs the coin.

The Archangel Uriel

Knowledge: Possible. He may very well know of what is happening during Proven Guilty, informed of such by the angels watching over the Carpenter house.

Opportunity: One supposes that if anything can get inside Harry's apartment, it's an archangel - but could he do it without leaving a trace?

Motive: Murky. He may look favorably on Harry, and likely would want to help the Carpenter family. However, Uriel is an Archangel, and might only tend to intervene in matters that are important to the grand scheme. Plus, he might only do such things when instructed to by God, which means that it's not Uriel but God we'd need to think about.

MO: Tricky. Uriel has given power to Harry in the form of Soulfire, but only indirectly; nothing as hands-on as technical support concerning magical constructs. If he's supporting Harry during the spell itself, then one would think Lash would notice.

[Gman]

Uriel is out of the picture becasuse of the rules of engagement as defined at the end of SmF.  No further reasons are needed.

It seems to me that your questions apply equally well if it is Uriel who did it, though.

I disagree with your interperatation of the Rules of Engagement that rules Uriel out. My top candidates are Uriel, Lasiel, The Gatekeeper and Eb. Yes, a talented Wizard could figure out what Little Chicago is for. That is way different that finding out the hidden flaw that Bob and Harry missed. That is like saying I can identify that is a 747 Boeing Airplane or I can find an undiscovered problem in the plane, troubleshoot and fix it. That is a short list. Who can get thru Harry's defenses undiscovered and have the ability I mentioned before. Bob mentioned that he was impressed with Little Chicago and none of the supervillians he worked for in the past could have done it.

[Mira]

I disagree with your interperatation of the Rules of Engagement that rules Uriel out. My top candidates are Uriel, Lasiel, The Gatekeeper and Eb. Yes, a talented Wizard could figure out what Little Chicago is for. That is way different that finding out the hidden flaw that Bob and Harry missed. That is like saying I can identify that is a 747 Boeing Airplane or I can find an undiscovered problem in the plane, troubleshoot and fix it. That is a short list. Who can get thru Harry's defenses undiscovered and have the ability I mentioned before. Bob mentioned that he was impressed with Little Chicago and none of the supervillians he worked for in the past could have done it.

  Lash is a mere shadow in Harry's head, even though she did separate herself from Lasciel.  Unless she took over Harry's body and he wasn't aware of it.  I believe if they knew about Little Chicago, both Eb and the Gatekeeper could fix it if they had the time to fully examine it and spot the flaw or even know what Harry's purpose was in making it in the first place.. They also had to get past Bob..  That assumes that they know about Bob, which I do not think they do.. That leaves Uriel as the likely one, though what his motives are at this point are unknown.

[svb1972]

  Lash is a mere shadow in Harry's head, even though she did separate herself from Lasciel.  Unless she took over Harry's body and he wasn't aware of it.  I believe if they knew about Little Chicago, both Eb and the Gatekeeper could fix it if they had the time to fully examine it and spot the flaw or even know what Harry's purpose was in making it in the first place.. They also had to get past Bob..  That assumes that they know about Bob, which I do not think they do.. That leaves Uriel as the likely one, though what his motives are at this point are unknown.

Lash might be a mere shadow, but she has in the past, along with the help of Subconcious Harry managed to do some fairly serious things.  I'm not saying Uriel is a bad choice, but I find it much more likely that it was Lash.

I just don't think it can be anyone but these two, and my money's on Lash.  I don't agree that the rules of engagement necessarily take Uriel out of the picture.  Though I do wonder what his motivation would be.  Lash has motive, oppertunity, and ability, she really fits much better.