switch

switch = true
mon = peripheral.wrap("monitor_0")
while true do
  local event, side, xPos, yPos = os.pullEvent("monitor_touch")
   if switch == true then
     switch = false
     redstone.setOutput("back",false)
     sleep(0.5)
   elseif switch == false then
     switch = true
     redstone.setOutput("back",true)
     sleep(0.5)
   end
end