system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What is a Markov chain?

I keep hearing about them and after looking it up I'm not much closer to figuring it out.
gpt
A markov chain is simply a "path" of various destinations, where each direction you take has a certain probability of happening.

For example, lets say every time you encounter a crossroads, you always take a random turn. This means that you have A->B(0.5)/C(0.5) chain. Thats a very simple markov chain.

An example of a slightly more complex chain would be:

1. Start in A
2. 30% chance to stay in A, 50% chance to go to B, 20% chance to go to C
3. B has 80% chance to stay in B, 10% chance to return to A, 10% chance to go to C
4. C has 0% chance to stay in C, 50% chance to go to A, 50% chance to go to B.

That is a markov chain. If you are in the chain, all you care about is your current position - if you are currently in C, it doesnt matter what probabilities A has, all that matters is what probabilities C has.