https://www.codewars.com/kata/snail/coffeescript

snail.coffee

snail = (array) ->
  # enjoy
  traversal = []  
  if array.length is 1 and array[0].length is 0 then return []

  row = 0
  col = 0
  turn = 0
  direction = 'E'
  while traversal.length < (array.length * array.length)
    traversal.push (array[row][col])
    # consider next square to visit
    if direction is 'E'
      col += 1
      # need to change direction?
      if col is (array.length - 1) - turn then direction = 'S'      
    else if direction is 'S'
      row += 1      
      if row is (array.length - 1) - turn then direction = 'W'      
    else if direction is 'W'
      col -= 1
      if col is turn then direction = 'N'      
    else if direction is 'N'
      row -= 1
      if row is (turn + 1) 
        direction = 'E'
        turn += 1
  traversal