Fell

local function checkFuel()
  if turtle.getFuelLevel() < 1 then
    turtle.select(1)
    turtle.refuel(1)
  end
end

local function column()
  while turtle.digUp() do
    turtle.dig()
    checkFuel()
    turtle.up()
  end
  turtle.dig()

  checkFuel()
  while turtle.down() do
    checkFuel()
  end
end

local function digmove()
  checkFuel()
  turtle.dig()
  turtle.forward()
end

digmove()
column()
turtle.turnRight()
digmove()
turtle.turnLeft()
column()
turtle.turnLeft()
digmove()
digmove()
turtle.turnRight()
column()