How to Play the Tile Game Widget on Your Mac
Apple provides a digital version of that old standby, the sliding tile game. Tile Game is a Dashboard widget on your Mac, so you can display it at any time by pressing the correct function key (F4 or F12, depending on the keyboard your Mac uses).
If you’re using a trackpad, display Mission Control (by swiping upward with three fingers) and click the Dashboard thumbnail.
Check out the Tile Game widget on a Dashboard.
If the Tile Game widget doesn’t appear on your Dashboard, click the Add button (bearing the plus-sign icon) at the lower left to display your available widgets. Click the Tile Game icon, and El Capitan adds it to your Dashboard.
Click the Tile Game window once to randomize the tiles and then click again to start playing. To move a tile to the free space, click the tile. The object of the game, of course, is to restore the image to its original pristine condition!
You can return to your applications and your El Capitan Desktop at any time by pressing the Esc key again or by pressing the Dashboard function key again.
One nice thing about Dashboard game widgets is that most of them save the current game (or position) when you close the Dashboard. That way, you can easily resume the game after you . . . well, get real work done.