https://www.codewars.com/kata/make-a-spiral/train/coffeescript

spiral.coffee

initialize = (size) ->
  spirals = []
  for i in [0...size]
    row = []
    for j in [0...size]  
      row.push 0
    spirals.push row
  spirals
  
inRange = (row, col, size) ->
  return row >= 0 and row <= (size - 1) and col >= 0 and col <= (size - 1)

isOccupied = (neighbors, size, spirals) ->
  for n in neighbors
    if inRange(n[0], n[1], size) is true and spirals[n[0]][n[1]] is 1
      return true

spiralize = (size) ->
  
  if size < 5 then return []
  spirals = initialize size

  row = 0
  col = 0
  turn = 0
  direction = 'E'
  last = size - 1

  while true
    
    # consider next square to visit
    if direction is 'E'
      spirals[row][col] = 1
      col += 1
      
      # make sure up, down and right neighbors are not occupied
      if isOccupied([[row-1, col], [row+1,col], [row,col+1]], size, spirals) is true then return spirals

      # need to change direction?
      if col is (last - turn) then direction = 'S'      
            
    else if direction is 'S'
      spirals[row][col] = 1  
      row += 1      

      # make sure left, right and down neighbors are not occupied
      if isOccupied([[row, col-1], [row,col+1], [row+1,col]], size, spirals) is true then return spirals

      if row is (last - turn) then direction = 'W'      
       
    else if direction is 'W'
      spirals[row][col] = 1  
      col -= 1

      # make sure left, up and down neighbors are not occupied
      if isOccupied([[row+1, col], [row-1,col], [row,col-1]], size, spirals) is true then return spirals

      if col is turn then direction = 'N'      

    else if direction is 'N'
      spirals[row][col] = 1  
      row -= 1

      # make sure left, right and up neighbors are not occupied
      if isOccupied([[row, col-1], [row,col+1], [row-1,col]], size, spirals) is true then return spirals

      if row is (turn + 2)
        spirals[row][col] = 1  
        direction = 'E'
        turn += 2

  spirals

00000
....0
000.0
0...0
00000

000000
.....0
0000.0
0..0.0
0....0
000000

0000000
......0
00000.0
0...0.0
0.000.0
0.....0
0000000

00000000
.......0
000000.0
0....0.0
0.0..0.0
0.0000.0
0......0
00000000

000000000
........0
0000000.0
0.....0.0
0.000.0.0
0.0...0.0
0.00000.0
0.......0
000000000

0000000000
.........0
00000000.0
0......0.0
0.0000.0.0
0.0..0.0.0
0.0....0.0
0.000000.0
0........0
0000000000

00000000000
..........0
000000000.0
0.......0.0
0.00000.0.0
0.0...0.0.0
0.0.000.0.0
0.0.....0.0
0.0000000.0
0.........0
00000000000