function iff (x,y,z)
  if a[x][y][z]==1 then
    turtle.select(1)
  elseif a[x][y][z]==2 then
    turtle.select(2)
  elseif a[x][y][z]==3 then
    turtle.select(3)
  elseif a[x][y][z]==4 then
    turtle.select(4)
  elseif a[x][y][z]==5 then
    turtle.select(5)
  elseif a[x][y][z]==6 then
    turtle.select(6)
  elseif a[x][y][z]==0 then
    turtle.select(16)
  end
end


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for x=1, #a do
  for y=1, #a[x] do
    for z=1, #a[x][y] do
      iff(x,y,z)
      turtle.placeDown()
      turtle.forward()
    end
  end

  turtle.turnRight()
  turtle.forward()
  turtle.turnRight()

  for y = 1,#a[x][y] do
    turtle.forward()
  end

  turtle.turnRight()
  turtle.turnRight()

  turtle.turnLeft()
  for y = 1,#a[x] do
    turtle.forward()
  end

  turtle.turnRight()
  turtle.up()
end