cobble

local cobble = 0
local max = 1500

while cobble < max do
  sleep(0.25)
  if turtle.detectDown() == true then
    turtle.digDown()
    turtle.dropUp()
    cobble = cobble + 1
    term.clear()
    term.setCursorPos(1,1)
    print("cobble: " .. cobble)
  end
 end