Kata

Problem

Give a matrix, print values in a counter-clockwise spiral form from upper left corner of the matrix.

Only single character will be given as element. You do not need to verify the edge cases of input.

Sample test case

spiral_print([
  ['a','b','c','d'],
  ['e','f','g','h'],
  ['i','j','k','l']
  ]) # -> 'aeijklhdcbfg'

spiral_print([
  ['a','b','c','d']
  ]) # -> 'abcd'