---
id: 5900f40d1000cf542c50ff20
challengeType: 5
title: 'Problem 161: Triominoes'
---

## Description
<section id='description'>
A triomino is a shape consisting of three squares joined via the edges.
There are two basic forms:



If all possible orientations are taken into account there are six:



Any n by m grid for which nxm is divisible by 3 can be tiled with triominoes.
If we consider tilings that can be obtained by reflection or rotation from another tiling as different there are 41 ways a 2 by 9 grid can be  tiled with triominoes:



In how many ways can a 9 by 12 grid be tiled in this way by triominoes?
</section>

## Instructions
<section id='instructions'>

</section>

## Tests
<section id='tests'>

```yml
tests:
  - text: <code>euler161()</code> should return 20574308184277972.
    testString: 'assert.strictEqual(euler161(), 20574308184277972, "<code>euler161()</code> should return 20574308184277972.");'

```

</section>

## Challenge Seed
<section id='challengeSeed'>

<div id='js-seed'>

```js
function euler161() {
  // Good luck!
  return true;
}

euler161();
```

</div>



</section>

## Solution
<section id='solution'>

```js
// solution required
```
</section>