Was it? Unless they had a before close up, you wouldn't see an existing crack before he broke it over his knee.  Or there is a trick to it, which apparently there is;

According to The Hardball Times. Here is the physics of it;

It also goes into how a bat is shaped and knowing where to apply the force at the weakest point.  In other words, the players that do it make a dramatic impression, but it apparently is something they studied and perhaps practiced before hand.

I'm almost done reading Skin Game and I have a question about Laschiel's coin.  When did it get freed and available for Hanah Asher to own it?  Last I knew, Harry buried it under a foot of concrete in the basement of his house.   Who dug it up?

Bob is the operating system, software and browser - spirit of intellect. If he can interpret the extremely complex and dense signal of Demonreach, and present is in a format Garry can understand the internet is a snap, especially as it means unlimited porn as an incentive.

Harry can actually therefore get a credit card and some use out of it even after it gets ruined, the chip or strip isn’t needed for on-line purchase.

An AI is really just a new type of spirit of intellect, not born from a brain but from a circuit board. The Fae can come into existence in so many ways, why not? Bob may be the bridge, so we might get Bob Junior born of Bob and the internet.

What a horrifying thought.

Naw, Col Klink.....

Bob can project on the walls, floors, ceilings of the Castle and can pick up electro magnetic frequencies. You just need a wireless router in one of the neighbouring houses too far away for Harry to disrupt to him to patch into the internet, and a nearby cell tower to patch in for cell phones.

Harry doesn’t need a computer, the Castle is now a computer. Harry has entered the silicon age. Literally.

Bob is capable of multi-tasking (at least at watching porn) so he should be interact with multiple users as his own local network for the castle users.

Initially his projections will be blue BUT we have seen him use other colours and Blue, green and red should be possible so he can go full colour. Harry will be so excited when the Mandalorian streams in the Dresdenverse (it’s currently late 2014) so several years to go.

Sound reproduction may be a problem, Bob isn’t a mimic and has only ever reproduced his own voice. In doing so it is either telepathic, of he is manipulating the air molecules to create sound. However as he can interface with a loudspeaker that ceases to be an issue.

Loudspeaker technology is old, Harry uses an old style radio but decent valve driven speakers date from 1912, over a hundred years old, so it would be relatively easy to custom build speakers using that tech (older by thirty years than the Munster mobile and amplifiers use valves today) with Bob acting as a carrier wave for them (he communicated via Harry’s office radio early in the series), Harry should be able to get full sound reproduction, even if Bob cannot provide it directly.Using a magic circle would cut off Bob’s carrier wave, but the tech would be old enough to likely hardly ever burn out because of Harry.

Whilst Harry can speak to Bob to dictate things it might be possible to rig up a keyboard. Get a slab of Castle Stone and have Bob project a keyboard touchpad on it. Bob should be able to discern the keys being touched and make the corresponding alpha numeric notation.

I don't believe a Faraday cage will block magic, only E-M radiation.  It therefore *WOULD* block tv's, radio, wifi, cellphone, etc.

You could get a landline or fiberoptic through a Faraday cage, but crossing a magic circle with such a line would break the circle.  The E-M spectrum crosses magic easily, though... wifi, cellphone, etc.