On Wed, 02 Jul 2003 09:12:38 GMT, "Joseph Meehan"
wrote:

For years now during the summer a strip of dead grass has appeared in my
back yard. I had assumed that there was a 2x4 buried there from the
construction. I probed for it but never found it.

I found it last week. A bright sunny reflections was on one end of it.
It seems the sun light in the evening is reflecting off a window which just
happens to have a shape that is focusing the light. As the sun moves each
day it creates a line. The extra heat (and it is quite warm) is just enough
to kill the top grass. I had not noticed it, but the line moves a little
over the summer as the sun moves in the sky.

How interesting. Rather like killing ants by using a lens to focus
light on them. Wonder why it doesn't happen more often, come to think
of it.