tunnel

args = {...}

if (#args == 0) then
    print("Usage: "..shell.getRunningProgram().." <length>")
    error()
end

torch = 0
t = turtle
blocks = args[1]

t.select(3)

for i = 1, blocks do
    t.forward()
    while t.dig() do end
    while t.digUp() do end
    t.digDown()
    torch = torch + 1
    if torch > 8 then
        t.turnRight()
        while t.dig() do end
        t.select(2)
        t.place()
        t.select(3)
        t.turnLeft()
        torch = 0
        end
    if t.getItemCount(16) > 0 then
        t.down()
        t.digDown()
        t.select(1)
        t.placeDown()
        for i = 3, 16 do
            t.select(i)
            t.dropDown(64)
        end
        t.select(3)
        t.up()
    end
end

for i = 1, blocks do
    t.back()
end