Write a function called unroll, which takes in a square array of arrays (i.e. a grid with n rows and n columns). An input could look like this: const square =[ [1,2,3,4], [5,6,7,8], [9,10,11,12], [13,14,15,16] ]; unroll should take in such a square array and return a single array containing the values in the square. You should obtain the values by traversing the square in a spiral: from the top. left corner, move all the way to the right, then all the way down, then all the way to the left, then all the way up, and repeat. For the above example, unroll should return [1,2,3,4,8,12,16,15,14,13