A stack of cubes is hidden. Collect clues about it and rebuild it. New puzzle every day.
Practice round
Need a reminder?
A clue is a floor plan with some squares lit. The number is the tallest stack among the lit squares. One lit square gives that stack's exact height. A total adds up every lit square. The top-left square is the back corner of the 3D picture.
Pick a game
Why Plato?
Prisoners chained in a cave, Plato said, mistake shadows on the wall for the real world. Somewhere in this cave sits a hidden stack of cubes, up to three high on a three-by-three floor. All you can see are its shadows, which are the clues. Collect them and rebuild the stack.
Play with friends
Each friend gets a few private clues. Nobody can solve it alone, so you trade clues in your group chat.
Your path
Pick a level
Make a puzzle for friends
Build a secret stack by tapping the squares. The page works out clues that point to exactly one answer and deals them to your friends. You'll know the answer, so you watch while they solve it.
Send each friend their own message
Cave master's view
This is the secret stack. Don't show it to your friends.
Join a friend's puzzle
Your friend made a hidden stack and sent you a message with your clues. Paste the whole message here.
The cave
How this works
- A stack of cubes is hidden. Rebuild it.
- Your team's clues are all below. Tap one and its squares light up on your board.
- Build your guess on the board, then tap Check my stack.
What do tallest, exact and total mean?
tallest: the tallest stack among the lit squares is that number. At least one has it and none is taller. exact: one square, and its exact height. total: all the lit squares added together.
Goal: rebuild the hidden stack. Your clues are the ones marked You. Your friends hold the rest. Paste what they send you, a whole message or a whole group chat.
How to read a clue
A clue tile shows a floor plan with some squares lit, and a number. The number is the height of the tallest stack among the lit squares. A tile with one lit square tells you that exact stack's height. So a clue with several lit squares only tells you the tallest of them: at least one lit square has that height and none is taller. The others can be lower, even empty. Some clues give a total instead: all the cubes in the lit squares added together.
On the floor plan and the board, the top-left square is the corner at the back of the 3D picture.