function selectNotEmptySlot()
 for i=1, 9, 1 do
  turtle.select(i)
  if turtle.getItemCount(i)>0 then
   i=10
  end
 end
end

function placeDown()
 selectNotEmptySlot()
 turtle.placeDown()
end

for i=1, 8,1 do
 for j=1, 2, 1 do
  for k=1, 16, 1 do
   placeDown()
   turtle.forward()
  end
  turtle.turnRight()
  turtle.forward()
  turtle.turnRight()
  for k=1, 16, 1 do
   placeDown()
   turtle.forward()
  end
  turtle.turnLeft()
  turtle.forward()
  turtle.turnLeft()
 end
 turtle.turnRight()
 turtle.forward()
 turtle.forward()
 turtle.turnLeft()
end