LumberJack

function proceed()
    turtle.digUp()
    turtle.suckUp()
    turtle.digDown()
    turtle.suckDown()
    turtle.dig()
    turtle.suck()
    turtle.forward()
end

for i = 9,1,-1
do
    for i = 4,1,-1
        do
        for i = 3,1,-1
        do
            proceed()
        end
        turtle.turnLeft()
        proceed()
        turtle.turnLeft()
        for i = 3,1,-1
        do
            proceed()
        end
        turtle.turnRight()
        proceed()
        turtle.turnRight()
    end
    for i = 3,1,-1
    do
        proceed()
    end
    turtle.up()
    turtle.digUp()
    turtle.suckUp()
    turtle.up()
    turtle.digUp()
    turtle.suckUp()
    turtle.up()
    turtle.turnRight()
    proceed()
    turtle.turnRight()
end
for i = 28,1,-1
do
    turtle.down()
end