A server is just some computer somewhere that other machines can connect to. You can get specialised hardware and network setups and other technical stuff, but you can also just use your personal laptop as a server by allowing people to connect to it. A server essentially boils down to someone leaving their computer on.
Wifi is just radio waves. You can think of it like people talking on a two-way radio, except instead of humans speaking it’s computers.
The people who own the apartments. Individual units have individual owners, shared areas have shared ownership by whoever owns the units unless specified otherwise. Maintenance of common areas is the shared responsibility of all owners.
I don’t follow, are you suggesting it’s impossible to own a single apartment in a block? As someone who lives in an apartment I own without owning the entire building, I can tell you that’s definitely false. You don’t need a landlord to make high density housing to work.
Most of the time, but only as long as the shuffle is actually random. A perfect riffle shuffle on a brand new deck will get you the same result every time, and 8 perfect riffles on a row get you back to where you started.