Water in a square fills its tank across that row and on every row below. A dry square makes its tank dry across that row and on every row above. It’s the rule of the puzzle, used as a technique: every mark you make spreads.
This is the first of the Aquarium techniques. Each page shows its technique on the same 10×10 from the game, Hard level 16.
The rule
- When you put water in a square, fill the rest of its tank on that row.
- Fill every square of the tank on the rows below as well.
- When you mark a square dry, dry the rest of its tank on that row, and every row above.
In a real puzzle
On the 10×10 every technique page follows, it’s first needed at step 3. Row 7 is numbered 10, so it’s all water (step 2). The tank holding its first square also has three squares in row 8, so those fill too.
How often you’ll need it
On 49 of the 50 Easy levels and every Medium and Hard one: 5.0 times per Easy level on average, 8.6 on Medium and 11.2 on Hard. It’s 13 of the 43 moves on the 10×10 here. In the game, a tap spreads the water or the dryness for you.