3D Matrix

W = {
     {{1, 1, 1},
      {1, 0, 1},
      {1, 1, 1},},

     {{1, 1, 1},
      {1, 0, 1},
      {1, 1, 1},
      {0, 1, 0},},

     {{1, 1, 1},
      {1, 0, 1},
      {1, 1, 1},
      {0, 1, 0},},

     {{1, 1, 1},
      {2, 0, 2},
      {0, 1, 0},},

     {{1, 1, 1},
      {1, 0, 1},
      {1, 1, 1},},

     {{1, 1, 1},
      {1, 1, 1},
      {1, 1, 1},},
     }

z = 1
y = 1
x = 1, 3
for z = 1,#W do
  for y = 1,#W[z] do
      for x = 1,#W[z][y] do
        slot = W[z][y][x]
        if slot ~= 0 then
          turtle.select(slot)
          turtle.placeDown()
        end
        turtle.forward()
      end
      for a = 1,#W[z][y] do
         turtle.back()
      end
      turtle.turnLeft()
      turtle.forward()
      turtle.turnRight()
  end
  turtle.turnRight()
  for A = 1,#W[z] do
    turtle.forward()
  end
  turtle.turnLeft()
  turtle.up()
end