local m = peripheral.wrap("left")

local myTimer = os.startTimer(1)
local perc = 0
while true do
  local event, timerID = os.pullEvent("timer")
  if timerID == myTimer then
    perc = perc + 10

    m.clear()
    m.setTextScale(1)
    m.setCursorPos(1,1)
    m.setTextColour(512)
    m.setBackgroundColor(colors.lime)
    for i=1, perc do
      m.write(" ")
    end
    m.setBackgroundColor(colors.black)
    myTimer = os.startTimer(1)
  end
end