LITS is also called Nuruomino. Its name comes from the 4 shapes you may use: L, I, T and S.
The rules
- The board is split into outlined areas. Each area is called a region.
- In every region, make exactly 4 boxes black. Together they must form an L, I, T or S.
- You can turn or flip a shape. A J counts as an L, and a Z counts as an S.
- All black boxes on the board must join up side by side. Corners that touch do not join.
- Matching shapes in different regions may not touch side by side. An L may not touch another L, even a flipped one.
- Never make a black 2 by 2 block. That is why the square O shape is not allowed.
- All other boxes stay white.
Here are the 4 shapes. L has 3 boxes in a line, with 1 beside an end. I has 4 boxes in a straight line. T has 3 boxes in a line, with 1 beside the middle. S has 2 rows of 2 boxes, shifted sideways by 1 box.
These are the classic rules. Quirk does not change them.
A worked example
This board has 4 rows and 4 columns. The letters show 3 regions: A, B and C.
| Column 1 | Column 2 | Column 3 | Column 4 | |
|---|---|---|---|---|
| Row 1 | A | B | B | B |
| Row 2 | A | A | B | C |
| Row 3 | A | B | B | C |
| Row 4 | C | C | C | C |
- Region A has only 4 boxes, so all 4 are black. They make a T: 3 boxes down column 1, with 1 beside the middle.
- Region B has a top part of 3 boxes in row 1. Its lower part, from row 2 down, also has only 3 boxes.
- So every shape in region B must use both parts. It needs row 1, column 3 and row 2, column 3 to cross over. Make both black.
- Now look at row 1, column 2. If it were black, it would close a black 2 by 2 block. That block is row 1, columns 2 and 3, and row 2, columns 2 and 3. Make it white.
- Row 3, column 2 can only join region B through row 3, column 3. If both were black, they would close a black 2 by 2 block with row 2, columns 2 and 3. Make row 3, column 2 white.
- Region B still needs 2 black boxes. Only row 1, column 4 and row 3, column 3 are left. Make both black.
- Region B is now an L: 3 boxes down column 3, with 1 beside the top end.
- Region C has 3 choices: an I along row 4, or one of 2 L shapes that go up column 4.
- Both L choices would touch the L in region B side by side. So region C is the I. Make all of row 4 black.
- Make row 2, column 4 and row 3, column 4 white. Then check: T, L and I are all different, no 2 by 2 block is black, and all black boxes join up.
The answer has these black boxes:
| Column 1 | Column 2 | Column 3 | Column 4 | |
|---|---|---|---|---|
| Row 1 | Black | White | Black | Black |
| Row 2 | Black | Black | Black | White |
| Row 3 | Black | White | Black | White |
| Row 4 | Black | Black | Black | Black |
Beginner techniques
Start with small regions
A region with exactly 4 boxes is easy: all 4 are black. A region with 5 boxes often has only 2 or 3 ways to fit a shape.
Boxes that every choice uses
List every way to fit L, I, T or S in a region. If all of them use a box, make it black. If none of them use a box, make it white.
The last corner
Look at any 2 by 2 square. When 3 of its boxes are black, the last box must be white. Also cross out shapes that would fill all 4 boxes.
Matching shapes stay apart
When you know the shape in one region, look at the regions next to it. Cross out any matching shape that would touch it along a side.
Keep the black boxes joined
Sometimes 2 black groups can only meet through 1 box. Make that box black. Cross out shapes that would leave a black group cut off.
Common mistakes
- Forgetting that a turned or flipped shape keeps its letter. J is an L, and Z is an S.
- Thinking 2 black boxes that touch only at a corner are joined.
- Making a black 2 by 2 block across the border of 2 regions. The rule counts there too.
- Putting more or fewer than 4 black boxes in a region.
- Only checking matching shapes inside one region. The rule is about shapes in regions next to each other.
Questions
Is LITS the same as Nuruomino?
Yes. Nuruomino is another name for the same puzzle, with the same rules.
Why is the square O shape not allowed?
4 boxes in a square would make a black 2 by 2 block. That block is never allowed, so O never fits.
Does every puzzle have one answer?
Yes. Each board in Quirk has exactly one answer. You can reach it by careful thinking, without guessing.
What sizes are there?
Boards go from 3 rows by 5 columns up to 6 by 6. Bigger boards have more regions.
What does Shape choices do?
It lists the shapes that still fit the region of the box you tapped last. You can cross out a choice, and bring it back later.
Is it good for beginners?
Yes. Quirk starts with short lessons that teach each shape first, and then each idea one at a time.
Related puzzles
Playing it in Quirk
Tap a box to make it black. Tap it again for a white dot, and once more to clear it. Turn notes on to mark a box as maybe black or maybe white.
Open Shape choices to see every shape that still fits a region. If you get stuck, a hint shows the next step and why it works. You can undo a move or start the board again.
