Every number once
Each row and each column holds every number exactly once, just like sudoku.
Odd and even make islands
Fill the grid.
Fill the grid.
Find the islands.
ODEVI is a number puzzle with a twist. Every row and column holds each number once. Odd and even neighbours join into islands, and small corner numbers tell you exactly how big each island must be.
Coming soon to the App Store
Try one now
Beginner · 4×4Pick a cell, then a number.
How it works
Three rules. One solution.
One clear rule set, exactly one solution per puzzle, from a two-minute warm-up to an hour-long expedition.
Odd and even make islands
Odd numbers are sand, even numbers are sea. Touching cells of the same kind (up, down, left or right) form one island.
Corner numbers are sizes
A small corner number tells you how many cells the island containing that cell has. Here every cell shows its size.
New to it? Learn ODEVI in 3 minutes walks you through a whole puzzle.
What's inside
60 puzzles, five levels.
Every puzzle is checked to have exactly one solution, so you never need to guess.
Beginner
- Grid
- 4×4
- Puzzles
- 12
- Time
- about 4 min
Easy
- Grid
- 5×5
- Puzzles
- 12
- Time
- about 10 min
Medium
- Grid
- 6×6
- Puzzles
- 12
- Time
- about 20 min
Hard
- Grid
- 7×7
- Puzzles
- 12
- Time
- about 35 min
Expert
- Grid
- 7×7
- Puzzles
- 12
- Time
- up to an hour
Made for thinking
Built to teach the logic, not just the rules.
Step-by-step tutorial
A guided 5×5 puzzle shows you how to reason your way to the answer.
Hints that explain
Stuck? A hint explains the next logical step, and can fill it in for you.
Assists, your way
Switch on mistake highlighting and odd/even counts per row and column, or play without.
Three stars to earn
One for solving, one for using no hints, and one for beating the par time.
Light and dark mode
Calm colours by day, deep sea by night. Easy on the eyes either way.
Plays offline
No sign-in and no connection needed. Your progress stays on your device.
Your privacy
ODEVI does not collect personal data. Your progress is stored on your device and nowhere else.
- No account
- No sign-in
- No analytics
Ready to find the islands?
ODEVI is coming soon to the App Store. Questions, bug reports and ideas are always welcome.