gravedigger

function refuel()
 turtle.select(2)
 turtle.refuel()
 turtle.select(1)
end

function turtle.turn()
 turtle.turnRight()
 turtle.turnRight()
end

refuel()
while true do
 turtle.digDown()
 turtle.down()
 turtle.dig()
 turtle.forward()
 turtle.turn()
 turtle.forward()
 turtle.turn()
 turtle.place()
end