system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do cartridge style video games work?
gpt
carts had all of the data on chips that were mounted on a circuit board with connector strips on it (similar to pins but flattened).  The gaming system had a reader where those connector strips attached and it was like the whole system was a big circuit board.

Think of it like if you had one game on a thumb drive that auto-executed when you plugged it into your USB drive.  That's not much different.