The spiral rule works if "pointer to" and "function returning"/"array of" alternate but it breaks if they don't, i.e., if you have arrays of arrays or pointers to pointers.

    int** arr1_of_arr2_of_arr3_of_ptr_to_ptr_to_int[1][2][3]

In this case, spiraling between [1], ×, [2], ×, [3], int is obviously wrong, the correct reading order is [1], [2], [3], ×, ×, int. (Edit: read × = *)

The Right-Left Rule is quoted less frequently on HN but it's a correct algorithm for deciphering C types: http://cseweb.ucsd.edu/~ricko/rt_lt.rule.html

I would name that algorithm "inside-out" instead of "right-left" if my understanding of its behavior is correct.

Aren't you supposed to treat multiple array or pointers as a group?

The fact that it's wrong if you try to generalize it beyond the examples given?

Does it? Here's one that I grabbed from cdecl.org:

  char * const (*(* const bar)[5])(int )

And its translation:

  declare bar as const pointer to array 5 of pointer to function (int) returning const pointer to char

This seems like what I'd get from the spiral technique.