--Get input
local lw={...}
local slot=1
local w
local l
if #lw~=2 then
  print("Usage: fill <length> <width>")
  return
end
for i=1,2 do
  lw[i]=tonumber(lw[i])
end
turtle.select(slot)
--
local function forward()
  if turtle.getFuelLevel() == 0 then
    if not turtle.refuel() then
      print("I need fuel!")
      while not turtle.refuel() do
        sleep(0.5)
      end
    end
  end
  while not turtle.placeDown() do
    if turtle.getItemCount(slot)==0 then
      slot=slot+1
      if not turtle.select(slot) then
        return false
      end
    else
      turtle.digDown()
    end
  end
  if not turtle.forward() then
    turtle.dig()
    turtle.forward()
  end
end
--Fill
for w=1,lw[2] do --width
  for l=2,lw[1] do --length
    forward()
  end
  if w%2==1 then
    turtle.turnRight()
    forward()
    turtle.turnRight()
  else
    turtle.turnLeft()
    forward()
    turtle.turnLeft()
  end
end