# Problem Definition

## Description

Given a matrix of *m x n* elements (*m* rows, *n* columns), return all elements of the matrix in spiral order.

**Example 1:**

```plaintext
Input:
[
 [ 1, 2, 3 ],
 [ 4, 5, 6 ],
 [ 7, 8, 9 ]
]
Output: [1,2,3,6,9,8,7,4,5]
```

**Example 2:**

```plaintext
Input:
[
  [1, 2, 3, 4],
  [5, 6, 7, 8],
  [9,10,11,12]
]
Output: [1,2,3,4,8,12,11,10,9,5,6,7]
```

## Notes

1. [LeetCode solution](https://leetcode.com/problems/spiral-matrix/solution/)