Lava

turtle.select(1)
local n = 1
while true do
for i = 1, 45 do
  turtle.placeDown()
  turtle.refuel()
  turtle.forward()
end
local turn
if n % 2 == 1 then
turn = turtle.turnRight
else
turn = turtle.turnLeft
end
turn()
turtle.forward()
turn()
if turtle.getFuelLevel() > 499950 and n % 2 == 0 then
  error("Done")
end
sleep(5)
n = n + 1
end