ELI5: Explain Like I'm 5

Fifteen puzzle

The fifteen puzzle is a game made up of 15 numbered tiles and a box. The tiles are placed inside the box in a random order, and you have to move the tiles around until they are all in order from 1-15. To play, you have to slide the tiles around in the box until all of the tiles are in the right place. You can only move one tile at a time, and you can't lift the tiles outside of the box. The goal is to finish the game so that all of the tiles are lined up from 1-15. It's like a super tricky puzzle!