This is a fun little puzzle game with CSS Grid. You have to turn off all the lights, but you can only toggle whole rows and whole columns.
If you get stuck, try the RESET button, or let the computer SOLVE it for you!
NOTE: it's not really a cake, so slightly off topic, but before you can eat the cake, you have to turn off the lights ☺ EDIT: You can easily edit the board dimensions in the HTML. It's a lot easier with a bigger board.