startup

term.clear();
term.setCursorPos(1, 1);
write("Gravel Processing Unit initialized");

while true do
  for i = 3, 16 do
    turtle.select(i);
    turtle.transferTo(1);
    turtle.select(1);

    if turtle.getItemCount(1) > 1 then
      while turtle.getItemCount(1) > 1 do
        turtle.placeUp();
        turtle.digUp();
      end
    end
  end

  turtle.select(2);
  turtle.dropDown(turtle.getItemCount(2) - 1);

  for i = 3, 16 do
    turtle.select(i);
    turtle.dropDown();
  end

  sleep(2);
end