Turtle: Wall

args = {...}
items = 0
currSlot = 1
le = args[2]
turtle.select(1)

function slot()
  if turtle.getItemCount(currSlot) == 0 then
    currSlot = currSlot + 1
    turtle.select(currSlot)
  end
end

function fuel()
  if turtle.getFuelLevel() <=2 then
    turtle.select(16)
    turtle.refuel(1)
    turtle.select(currSlot)
  end
end

function up()
  for i = args[1],2,-1 do
    fuel()
    turtle.up()
    turtle.placeDown()
    slot()
  end
  fuel()
  turtle.back()
  turtle.place()
  slot()
  le = le - 1
end

function down()
  while not turtle.detectDown() do
    fuel()
    turtle.down()
    turtle.placeUp()
    slot()
  end
  fuel()
  turtle.back()
  turtle.place()
  slot()
  le = le - 1
end

while le ~= 0 do
  up()
  if le ~= 0 then
    down()
  end
end