The 15-Puzzle is a game consisting of 15 squares numbered from 1 to 15 and an empty square in which the direct horizontally or vertically neighbor square/tile can be moved into. The goal is to move the tiles into the correct order from top to bottom, so each number is ordered correctly. By hovering over the tiles, you can see which can be moved and which cant. Non-moveable tiles will stay blue, while moveable tiles turn purple and smaller. Keep in mind that text in the frontend is written in german, since i'am a german developer.
If you want to see the correct order in which the puzzle should be in, just press the left button that's labeled with "Kacheln sortieren".
The website will shuffle the puzzle randomly and automatically, if it's loaded. However, by pressing the right button that's labeled with "Neues Spiel", you can also shuffle it again and start a new game