What are your favourite analogies for explaining difficult or complex concepts?

When people ask me about email, I like to tell them it's just like using the Fediverse.

Truly great analogy

IPs and Ports are like street address and room number.

LLMs ie chatGPT are like a Galton Board. Your sentence is the bucket of balls at the top, each ball is a word or 'token', and the LLM is the arrangement of pegs on the board. Training the model is like moving the pegs around until the pattern you get at the bottom is desirable.

Computers are essentially rocks we have tricked into doing math.

Don’t oversimplify though, remember you need to put lightning into it first!
- Might we say they are "shocked rocks"?
"Teaching sand how to think was a mistake".
Sand, light, lightning, and metal

"Framerules" in Super Mario Bros. speedrunning on NES is probably the most memed analogy for a (very slightly) more complicated concept I know of.

The game can only send you to a new level every 21 frames (about .3 seconds), so there are tons of levels where timesaves don't lead to any benefit, because you have to save a full .3 seconds in order to see any benefit.

In the community, this has been explained with the same analogy so many times that "Imagine there's a bus" has become a well-known meme.

So, imagine there's a bus that only leaves the station every .3 seconds (21 frames). Because the bus only leaves at the times on its schedule, arriving early for the bus doesn't get you to your destination any faster, because you still have to wait for the time the bus will leave. For this reason, any new time saves in SMB1 must reach a new "framerule" (get there early enough to catch the previous bus) for there to be any real timesave.

Thanks darbian.

"ActivityPub is like using email pretty much."

That's my favorite analogy to use when I explain what the fediverse is sometimes.

When I have to explain how email works, I walk them through the process of drafting a letter, placing a stamp on it, dropping, it in a mailbox, etc. The stamp and the address contain the "routing information if you will." I call the SMTP server, the postal service. I refer to the IMAP server as like the mailbox.

I usually explain wormholes by folding a piece of paper and pushing a pencil through it /s

Yeah, I always explain those concepts using analogies of how my ex wife used to do things. E.g. to explain quantum mechanics I usually tell them how my ex wife used to cheat on me and so on.

Blood pressure in relationship to fluid. Just like a water hose. More fluid = more pressure.

The vocabulary of a language is like the fur of a beast: sure, it's highly visible, but what's inside (the grammar, or the beast itself) matters more.

I get the analogy but don't agree with the reasoning. Or maybe it depends on the circumstance. But for foreign languages I would suggest it's the other way round: The fur (grammar/prononciation) might look (sound) nice, but it's the vocabulary that bring the actual meaning to whatever you say.
- The circumstances when I use this analogy are mostly language evolution, borrowings, and their overall impact on a language. I'll use two English example sentences to demonstrate this:
  
  I adore their potatoes with jerky, amigo.
  
  *Apple me eats two.
  
  Which one of those sentences is recognisably English? It's the first one because, while it's full of borrowings*, it still abides to the morphological and syntactical rules of the language. In the meantime, the second sentence is rubbish, even if it uses well-established native vocab - because it doesn't abide to English syntax and morphology.
  
  Or, by the analogy: the first sentence might've changed the fur of the beast, but the beast inside is still the same. The second one plopped that beast's fur over something else, but the beast isn't there any more.
  
  (The "pronunciation" / phonology is a third can of worms. It doesn't work well with the fur vs. beast analogy.)
  
  *"adore" from French, "their" from Old Norse, "potato" from Taino, "jerky" from Quechua, "amigo" from Spanish. Only "I" and "with" are native.

Like a balloon and something bad happening.

I found you Bender

I tell my students that going to a challenging class and not participating is like going to the gym and watching people work out. It is not only fairly useless to your goal of improving yourself, it creeps out everyone else and makes it feel like an unsafe place to try new things and make mistakes.

That's a broad topic as I use different analogies for different subject matter. What subject(s) are you thinking of?

I think my question was not clear. The very intention of the question is to tell **any **complex topic you've encountered that you've found a surprisingly understandable analogy of. there is no constraint of any subject.
- There were dinosaurs. They died. They became oil. We use that oil to move. It’s an analogy to anything you want if you are very high.

DNS is the phonebook of the internet and other networks.

I was diagnosed with clinical depression around 2013, but definitely suffered from it as early as 2007. At first I was very embarrassed and ashamed of it, especially when I first started taking antidepressants. I didn't want to take medicine / be in therapy for the rest of my life. It didn't help that my parents were under the impression that I could eventually get over it -- saying things like "you don't want to be in therapy forever do you?" "You want to eventually not have to take antidepressants, right?" After a few years, I stopped trying to "cure" myself and began to accept that it's going to be a part of my life (and that's okay). Even my parents slowly started to realize that it will always be present. In fact, I started to become a little grateful for my depression, because I think it gives me a unique perspective on the world and life in general. I'm pretty open about my diagnosis now. I've had a few people tell me they're taken aback by how honest I am about my struggles. I tell them that, for me, living with depression is like being grass. Too much happy, yellow sunshine will make you dry, dead, and brown, and too much gloomy, blue rain will make you gray and root-rotted. You need a healthy balance of both to be lush and green (my favorite color).

Explain any one particular complex topic using an analogy you found interesting or easily understandable.