Four digits, none repeated. Ten turns, counts only. Everything else on this list is a variation on that.
Every board has exactly one answer, and you get one attempt at it. What changes between tiers is how much of the deduction is already done for you — and how much of the board you can afford to ignore.
The same code and the same ten turns, side by side. You see the shape of your opponent's progress — their turn count and their counts — and never their digits. Land a ●0 ○0 or a ●0 ○4 and the room plays a guess of its own choosing against them. It costs them a turn they did not spend.
Send the room code to the other player. First one in waits in the lobby. Letters and numbers only.
There is a hidden four-digit code. No digit appears twice. You guess; the game tells you how close you were; you use that to rule things out until only one code is left.
You are not trying to guess lucky. You are trying to make each guess tell you the most.
Every guess comes back with two numbers. ● is how many digits are right, and in the right slot. ○ is how many are right, but in the wrong slot.
In Assist, each slot is coloured instead of counted, so you are told exactly which digit was right where.
Assist is genuinely easier — it hands you the placement you would otherwise have to deduce. Classic is the game; Assist is an aid. Pick before a run starts: in Classic the toggle is not there at all, so you cannot bail out halfway.
These two feel like you got nothing. They are the strongest results on the board.
Both get their own sound, so you never mistake one for the other.
Open the scratchpad and you get a grid. Rows are the ten digits. The four columns are the four slots, left to right. Tap a cell to cycle it:
The habit worth building: when a guess comes back ●0, none of those four digits are in the slots you put them in — go and mark four ✗ straight away. Most of a solve is bookkeeping you did not skip.
When a digit is out of the code entirely — a ●0 ○0 kills four at once — tap the digit itself at the left of its row. That rules it out of all four slots in one tap, and the digit greys out so you can see the row is dead. Tap it again to clear the row.
Your matrix reads back onto the board above, so you are not scrolling down to remember what you already worked out. A digit you ruled out everywhere goes grey like a ✗ cell — on the keypad and in your past guesses. A digit you confirmed goes green like a ✓ cell, but on the keypad only: "this digit is in the code" is a claim about the digit, not about any particular slot, and the keypad is the one place with no slots to confuse it with.
Those are your conclusions, not the game's, so a greyed key still works. You might be wrong, and the game will let you find out.
Undo and Redo are there for when an assumption turns out wrong three marks later. You should not have to clear the whole grid to back out of one bad idea.
This one is optional, and it is the strongest tool in the game. A cluster records something the matrix cannot: “exactly N of these digits are in the code.”
Tap a digit in the Clusters strip to tag it, then set how many of that group are in. Up to three clusters at once, and their colours tint the matrix so the two halves read as one tool.
Clusters sits collapsed under the matrix. If you never open it, nothing is lost — but this is the technique that separates a good solve from a lucky one.
Each one is six locks and a door that will not open until you have all six. Same craft, different rooms — pick a case for the story, not the difficulty. Each keeps its own progress.
Rows are the ten digits. The four columns are the four slots, left to right. Tap a cell to cycle: blank → ✗ ruled out → ? maybe → ✓ confirmed. Tap the digit at the left of a row to rule it out of all four slots at once — tap again to clear the row.
Tap a digit to tag it into a cluster. Use one when you know exactly how many of those digits are in the code — for example "one of 8 or 9". Then set the count. Cluster colours also tint the matrix.
No clusters yet.
Your guesses and scratchpad will be lost. There is no way back to this board.