1

a = 10

 for i=1,a do

   turtle.dig()

     while turtle.detect()==true do
     turtle.dig()
     os.sleep(0.5)
     end

   turtle.digUp()
   turtle.digDown()
   turtle.forward()

 end

 turtle.digUp()
 turtle.digDown()

 for i=1,a do

 turtle.select(1)
 turtle.placeDown()
 turtle.select(2)
 turtle.placeDown()
 turtle.back()
 turtle.select(3)
 turtle.place()
 turtle.select(4)
 turtle.place()


end