Tetrominoes LITS is a logic puzzle with a difference! It combines elements of the tetris game with a rich helping of logic rules to create a challenging and engaging puzzle. If you have heard of tetromono puzzles or have seen our f**ree printable tetromino puzzles here**, but not sure how to completely them – read on!

Like many of the very best logic puzzles, the rules are deceptively simple. Follow the rules and use deductive reasoning and you will have no problems completing these puzzles.

## What Is Tetromininoes LITS Logic Puzzle?

Tetrominoes LITS logic puzzle is a grid based puzzle where you have to place tetris style shapes into ‘regions’ marked on the grid. You can see on the image below how the regions in Tetrominoes LITS puzzles look.

A ‘tetris’ style shape made from four squares must be placed in each one. The shapes are L, I, T and S and look like this:

However they can be reversed, mirrored, changed direction etc, however they will always be the shapes shown made out of four squares.

Sounds simple so far…?

Well, here’s the rules ðŸ™‚

## Tetrominoes LITS Logic Puzzle Rules

Here are the rules to help you complete the puzzles successfully:

**1/ Tetrominoes must formm a orthogonally contiguous area. **

An **orthogonally contiguous area** is a collection of shapes that are all connected by their edges, and that can only be connected by edges that are **either horizontal or vertical**. In other words, there are no diagonal connections between the shapes.

So, in the context of tetrominoes, an orthogonally contiguous area would be a group of tetrominoes that are all touching each other, either horizontally or vertically, but not diagonally.

The rule that all tetrominoes must form an orthogonally contiguous area means that you** cannot have a tetromino that is just floating in the middle of the board, with no other tetrominoes touching it**. All tetrominoes must be connected to each other in a way that forms a single, unbroken shape.

**2/ When two tetrominoes in adjacent regions share an edge, they must not be of the same type.**

This means that, for example, two ‘T’ shape tetrominoes can not be touching.

**3/ Tetrominoes can not form a 2×2 block**

If we look at the solution below, you will see what this actually means in practice:

Note how following the rules:

All tetromino shapes are touching either vertically or horizonally

There are no shapes the same which are touching

There are no 2×2 blocks of tetrominoes.

## How to Solve a Tetrominoes LITS Logic Puzzle

Here are some tips for completing Tetrominoes LITS Logic Puzzles.

#### 1/ Start Small!

Look for the smaller regions as these give less options. In the example below, this region can only fit an S shape tetromino.

#### 2/ Mark What We Know

So while we know this region can only take an S shape tetromino, there are two places it can be placed. Therefore let’s mark the squares where we know, which ever way the S is placed, will be covered.

Additionally, I am adding ? to the cells where the S ‘might’ go.

And I have also added an X where I know a tetromino CAN’T go (because we cannot have 2×2 squares, therefore where I have added an X must stay blank to meet this rule.

#### 3/ Eliminate Where Possible

Work through the grid using the rules to complete what we know. Inn the example below, you can see I have marked on the left, cells that could either be an I or L and on the right another group of cells that can only be an S.

However, as above, there are alternatie placings, so I have just written on grid what we know following the rules.

#### 4/ Keep Following the Rules

As you complete more cells with tetrominoes, so it becomes clearer where tetrominoes can and can’t be placed.

In the example below, we while we knew that either an I or L could go here, on further reflection we know it must be an I as it needs to touch the tetromino above (which we now know will be an L as two touching tetromino shapes can’t be the same) and the tetromino below:

So we can fill in the tetromino above too:

#### 5/ Use the rules to narrow options

The rules will help us narrow the options. In the example below, we know that** two touching shapes cannot be the same**. Therefore we know that while there are different options for both of the S shapes below. In order to ensure that they don’t touch each other, that only gives us one option of where the S shapes are placed. So we can remove the ?.

which means we can complete these S shapes like this to ensure that they are not touching:

**6/ Keep adding tetromino shapes**

Keep following the rules and adding shapes. In the example below, we know that either an I or L shape can be used here to ensure that the shapes touch. As two touching shapes cannot be the same, and we’ve got an I already placed, this must be an L.

Eventually the grid will be complete and look something like the image below. This looks quite messy and is difficult to follow. If I was doing this in ‘real life’ I would use a pencil to mark the cells which I know must be empty, and I would darken the cells where the shapes are placed (once I know they are correct) to make the grid easier to follow.

## Tips for Completing Tetrominoes Logic Puzzles

Here are some tips for completing LITS puzzles as a beginner:

- Start with small regions where you have limited options.
- Focus on connectivity: Remember that all shaded cells need to be connected, forming one continuous shape. Try to identify blocks of shaded cells and think about how they can be connected without violating the puzzle rules.
- Use the elimination strategy: Look for cells that must be shaded or unshaded based on the adjacent cells. For example, if 3 cells in a 2×2 block are shaded, you know the fourth can not be. Similarly, if a shaded block is the shape T, you know that the touching tetromino block can’t be.
- Avoid isolated shaded cells: Since shaded tetromino blocks must touch orthogonally, avoid creating isolated shaded cells that don’t connect to the rest of the grid.
- Make educated guesses (in pencil ðŸ™‚ ): If you reach a point where you cannot make any more deductions, you may need to make educated guesses on the remaining uncertain cells. Remember to keep track of your assumptions and be prepared to backtrack if necessary.

Remember that practice is key in improving your skills with LITS puzzles. By solving more puzzles, you’ll become more familiar with the common strategies and patterns involved.