How to play
Gameplay
How to play
Connect two diagonally opposite numbers.
+ − × ÷
A line is valid if the sum, difference, product, or quotient of the two numbers appears in either of the other two corners.
Example
Connect 8 and 2: 8 ÷ 2 = 4 and 8 − 2 = 6. The line is worth 2 points.
Score
Every matching operation is worth one point. Matches on both sides add together, so one line can be worth several points.
Line colours
Drag between valid diagonal corners
Touch a number and drag to a valid diagonal corner. Correct lines remain faintly behind the numbers. Draw a found line again to inspect its operations.
No match
A wrong drag costs 10 seconds. The round ends after the third mistake.
Review found lines
Tap a number tile without dragging to highlight it and every previously found line connected to it. The other endpoints are outlined in a different color. The highlights fade automatically, or disappear immediately when you make a move or the round ends.
Hints
Tap the lightbulb and choose to watch a rewarded ad. After the completed ad, resume the game and one missing line will blink. Closing the ad early gives no hint. Normal boards and Expert 3×3–4×4 have 1 hint; Expert 5×5–6×6 have 2; Expert 7×7 has 3. Hints require an internet connection. Fewer used hints rank higher after completion percentage.
Leaderboard order
Results are ranked by completion percentage, then by fewer hints used, shorter time, higher score, and finally the newer date.
Game modes
Normal
Only diagonals within 2×2 squares are considered.
Expert
In Expert mode the connected numbers may be opposite corners of any rectangle, not only an adjacent 2×2 square.
Unlocking Expert boards
Expert boards unlock as your thinker reaches the required karate belt rank. Normal boards of every size are always available.
10s+
Start with 10 seconds. Every correct line adds 10 seconds for each point it is worth.
Karate
IQ points
The IQ reward shown above START is determined before the round by the mode, board size, number range and time limit. A 100% clear awards the full amount. For an unfinished board, the completion ratio is raised to the fourth power and half of the resulting reward is awarded, rounded down. This deliberately makes meaningful IQ rewards depend on near-perfect clears; below 80% completion the reward is only negligible. Zero score earns nothing. IQ points stay on this device and advance your thinker through the karate belt ranks, from white belt to black belt dan 10.
Karate ranks
The colors follow the Kyokushin karate belt order: white, orange, blue, yellow, green, brown, and black.
Challenges
The same board for everyone
Challenge mode lets several players solve exactly the same generated board. A challenge is valid for 30 days.
Create and share
Choose the board settings, open Challenge friends, and create the challenge. You can also turn the current board into a challenge from the pause or result screen. Share its QR image, then wait for the others or start when everyone is ready. Locked Expert boards cannot be used.
Accept and continue
Choose Accept a challenge, then scan the QR code with the camera or select its image. Starting uses this installation’s only attempt. Progress is saved continuously, so an unfinished challenge can be continued from Saved challenges. Finished or deleted attempts cannot be replayed. Hints are allowed and counted.
Results and local ranking
After finishing, share your signed result QR image. To build the ranking on Challenge results, import each player’s result by scanning it or choosing the image. Ranking order is completion percentage, fewer hints, shorter time, then higher score; pace is also shown.