length = {...}
length[1] = tonumber(length[1])
if type(length[1]) ~= "number" then
	error("usage: "..shell.getRunningProgram.." <length>")
end

print("step 1: submerge turtle 1 block under lava in a long lava lake")
print("step 2: place bucket in slot #1")
print("step 3: press enter and watch the magic happen :3")

function ref()
	turtle.placeUp()
	turtle.refuel(1)
	turtle.placeDown()
	turtle.refuel(1)
	turtle.place()
	turtle.refuel(1)
end

function forward()
	while not turtle.forward() do
		turtle.dig()
		turtle.attack()
	end
end

for i=1,length[1] do
	ref()
	forward()
end

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

for i=1,length[1] do
	ref()
	forward()
end

turtle.up()
turtle.up()
turtle.up()
turtle.forward()
turtle.forward()