Cfrgtkky

Here's a short and easy one:

Me and my friend were hanging out in a restaurant and on the way back we saw a strange looking, abandoned castle. We wanted to check it out, so that's what we did.

The lights were off, and we saw 3 switches, and it wasn't immediately obvious what they did. For example, when one of those switches was turned on, it turned off the lights although the other 2 switches were on.

I told my friend it was weird that each switch didn't just turn on a light and asked if he knew how these lights worked, and he said:

______, duh!

Is the answer to this

Series-ly?

Because

The lights and switches work in series (as opposed to in parallel)?

Maybe your friend said

Alternating current, duh!

His comment is condescending because it is obvious to him since he is

George Westinghouse, inventor of AC, and it's his castle you're standing in front of. I don't know how these switches' reliance specifically on AC causes this behavior unless it is simply a multiway switch setup, which has already been suggested. But he probably does because he rigged them up using one of his proprietary train signal switching techniques.

Electricity, duh!
You asked how the lights worked, not the switches. Your friend responded in kind.

I think the answer to this problem is that:

The switches work fine - it's the lights that don't work.

Because:

This is an abandoned castle. The lights were already out when you arrived, so perhaps the bulbs need replacing or the electricity has been cut off.

Lights-out, duh!

The way that the switches work reminds me of

Lights Out, a game where pressing a button reverses the state of the buttons around it. It is not intuitive to turn all of the lights on or off.

How about silly answer?

Boolean logic, duh!


Because when you write down how the switches work, you get 5 boolean expressions, which of course can be simmlified and written down as a single expression in CNF form.

However the answer seems silly, because on one side i doubt the friend had the time to figure the expressions.
On the other side, friend just could have heard that there is such thing as booolen logic, and that any expression can be written down in CNF form, and remembered it, however unlikely it is
It could be also said that the friend studied serious maths including boolean logic.


I am not sure I should have posted the answer, because in reality it's just a more clever way of saying Multiway switching, Series-ly and Code/Combination

Partial answer (?):

There's a lot of weird stuff on this one, and I don't know if it's intended to guide us towards the solution, but abandoned castles shouldn't have electricity in the first place, and if the lights were off, you probably couldn't see the switches either. I'm maybe guessing this is a toy castle rather than a full sized-one, but this is just a very incomplete attempt at an answer.