function attack()
 while true do
  turtle.attack()
  check()
  sleep(.5)
 end
end

function check()
 if turtle.getItemCount(16) > 0 then
  for i=1, 16 do
   turtle.select(i)
   turtle.dropDown()
  end
 turtle.select(1)
 end
end

local function startup()
 term.clear()
 term.setCursorPos(1,1)
 print"Turtle Powered Mob Farm starting..."
 attack()
end

local rtn, error = pcall(startup)
if not rtn then
 print("Error: "..error)
print("Exiting")end