Trying to make sense of challange 3 in Arrays tutorial

[nene]

Hi I'm trying to make sense of challenge 3 in arrays tutorial:

Write a program that adds a 1-row leading axis to an array.

First off, I have no idea what this "1-row leading axis" might be. Perhaps I didn't read the tutorial close enough.

But even worse, when I look at the examples in this challenge, they make no sense to me either:

Example: [1 2 3]
╭─       
╷ 1 2 3  
        ╯
Test 1: 1_3_1_5
[1 3 1 5]
Test 2: 5
5
Test 3: ↯2_3⇡6
╭─       
╷ 0 1 2  
  3 4 5  
        ╯

Like, the the expected output is exactly the same as the input?

I tried solving it by the identity function ∘. But that answer was rejected.

There must be something about the expected output that's invisible to my eye.

[nene]

Nevermind, I think I figured it out. I didn't realize that

[1 2 3]

and

╭─       
╷ 1 2 3  
        ╯

are different things. A one-dimensional array, v/s a two dimensional array.

And the task was to just wrap the input inside an array.

[nene]

I have to say though that this challenge was by far the hardest so far.

I managed to solve all the other ones in the Array tutorial, but this one is like... even when I gave up and looked at the solution, I was completely puzzled. Only after carefully studying the solution was I able to finally understand how it's done.