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# challenge instruction question.

Hi so in the instruction: "Here is a multi-dimensional list of musical groups. The first dimension is group, the second is group members." So my question is: Which one is the group and which one is the group members in the given list? or what do they mean by "The first dimension" ???

Thanks

groups.py
```musical_groups = [
["John Lennon", "Paul McCartney", "Ringo Starr", "George Harrison"],
["Salt", "Peppa", "Spinderella"],
["Rivers Cuomo", "Patrick Wilson", "Brian Bell", "Scott Shriner"],
["Chuck D.", "Flavor Flav", "Professor Griff", "Khari Winn", "DJ Lord"],
["Axl Rose", "Slash", "Duff McKagan", "Steven Adler"],
["Run", "DMC", "Jam Master Jay"],
]
```

Hey judeokain, thanks for your question, multi-dimensional lists can get awkward and complex very quick, so hopefully I can help in explaining them.

A multi-dimensional list is a list of lists, i.e. say if I had one huge box, and I filled it with lots of other boxes, I would have a box of boxes, right? And If were to fill those boxes with more boxes, I would have a box of boxes of boxes, and so on... So a multi-dimensional list is a list containing multiple lists. Specifically in this challenge it is a 2 dimensional list (a list of lists).

The first dimension is referring to each list within the musical_groups list, meaning that each of these lists forms a group. In this particular example, think of it as each opening bracket '[' means the start of a new group, and the closing bracket ']' is the end of that group.

The second dimension refers to the list of individual members of a particular group.

Heres an example:

musical_groups[1] is the Beatles (because lists are 0-indexed) and the members of the Beatles are John Lennon, Paul McCartney, Ringo Starr, and George Harrison. If we were to assign a variable with musical_groups[1], we would creating a single-dimension list containing the names of members of the Beatles.

```the_beatles = musical_groups[1]

print(the_beatles[0])
```

The above print statement would give us "John Lennon".

I hope that helps, feel free to comment and ask any further questions.

Ohhhh! I get it now. Thanks a lot!