Okay, let's try to explain the Artin-Tits group in a way that a 5-year-old could understand.
Imagine you have a group of friends at school. You all like to play games together, but sometimes it's hard to keep track of who's in charge of what game and who gets to make the rules. That's where the Artin-Tits group comes in!
The Artin-Tits group is like a special group of friends who work together to make sure that everyone knows the rules and who's in charge of each game. It's made up of some really smart grown-ups who study really complicated math stuff. But they use their smarts to make things easier for the rest of us.
The Artin-Tits group is named after two of these smart grown-ups who worked together to figure out how to organize the rules for lots of different games. They found out that you could use something called "generators" and "relations" to describe how each game is played.
Now, when you play a game with the Artin-Tits group, you don't have to worry about who's in charge or what the rules are. They've already figured it all out and made a plan for how to play the game properly. And that's the Artin-Tits group in a nutshell!