This is an old trick but it works...
1) Download the attached file
2) Unzip it
3) Print the included .pdf on standard overhead transparency.
4) Carefully cut out one of the 9 rectangles just outside of the lines
5) Nip off about 1mm of each corner
6) Slide the resulting rectangle under the edges of the screen.
Enjoy!
P.S. I\'ve submitted this to the \"Other cool stuff\" download section as well
