http://kor.i2p/books/The%20C%20Programming%20Language%20by%20K&R/chapter5.html
If a two-dimensional array is to be passed to a function, the parameter
declaration in the function must include the number of columns; the number of
rows is irrelevant, since what is passed is, as before, a pointer to an array
of rows, where each row is an array of 13 int s. In this particular
case, it is a pointer to objects that are arrays of 13 int s.