For the benefit of anyone who missed the earlier discussion of the
device, you can see the web page at http://www.iedu.com/ssq/, with
line drawings that actually pre-dated digital cameras.

There's a more recent photo of one of the original (25+ years old)
squares at http://www.iedu.com/ssq/ssq_photo1.jpg. The notch in the
fence was made by a 1/4" straight router bit. That information and a
minimal amount of thought should lead to insight as to why the "web"
between the arms of the square more or less doubled its usefulness -
something that the non-woodworking types could never pick up on.

If anyone finds the design interesting, now would be the time to snarf
the images, because they'll disappear from my server sometime in the
week ahead. It's time for me to put this piece of my woodworking life
behind me and move on...

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto