---
id: 5900f40d1000cf542c50ff20
challengeType: 5
title: 'Problem 161: Triominoes'
---
## 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?
## Instructions
## Tests
```yml
tests:
- text: euler161() should return 20574308184277972.
testString: assert.strictEqual(euler161(), 20574308184277972, 'euler161() should return 20574308184277972.');
```
## Challenge Seed
```js
function euler161() {
// Good luck!
return true;
}
euler161();
```