This is not a practical question!

I am not asking how one would accomplish the end-goal of this code in a production environment. Rather, this question is about how C works. The given example is demonstrative, not practical.

Lets say I have 3 existing arrays, each of type int[10]:

int first[10] = {0};
int second[10] = {0};
int third[10] = {0};

Lets say I want to create a 2d array which stores these arrays:

int outer[][10] = {
    first,
    second,
    third,
};

The above would not work, as, in C, references directly to an array degenerate into pointers to the array's first element, meaning the above is stating:

// Not valid C, just demonstrative
int outer[][10] = {
   int (*),
   int (*),
   int (*),
};

rather than the intended result of:

// Also not meant to be valid C
int outer[][10] = {
    int[10],
    int[10],
    int[10]
};

Is it possible to initialize a 2d array in this way, with a list of array objects, rather than pointers to array elements?

int outer[][10] = {
  first,
  second,
  third,
};

If this is not an option:

int* outer[][10] = {
  first,
  second,
  third,
};

Then, consider the supported structure assignments:

typedef struct {
  int _[10];
} array;

const array first = {0};
const array second = {0};
const array third = {0};

array outer[] = {
  first,
  second,
  third,
};

The elements are accessed like outer[1]._[1] = 0;.