a sawfish extension:care-eyes

May be there are many people working just like me,staring at the monitor for a long time.However you are busy,must you take a rest every one or two hours,otherwise,your body will be wore out.
Until now,I have several problems which make me not so good.I can't see clearly those far from me.And after sitting for a while,my neck aches.But often I forgot my discomfort when I am coding or seeing a film or playing a game.So I write this extension to remind me to take a rest.
You can download it here.
Put it to your sawfish's extension directory,and add the following lisp expressions to your sawfish configure file:
(require 'care-eyes)
(eye-care-init 7200 300 nil nil)
here,7200 is the seconds you may work for a longgest time without a rest,i.e. 2 hours,and then you will rest for 5 minutes.
Generally you can ignore the last two arguments,the extension will call xscreensaver to activate the screensaver.Before that,it display a message like this by default:
have a rest,care your eyes:)
You will be able to customize it by set the "resting-message" variable.
That's all,any suggestion or problem,mail to fvwmer[AT]gmail[DOT]com.