Lindy apparently subscribes to the saying "A cat in the house is worth two
in the back yard."  I was eating my breakfast in the living room this
morning, as I always do.  I looked out the sliding glass door and saw a gray
cat in the back yard.  At first, I assumed it was Nanki-Poo, who is mostly
gray.  Then I realized it couldn't be, because it didn't have any white on
its face.

Lindy apparently saw it at the same time.  She immediately ran over to the
sliding door and began telling that cat where to go.  Really!  Such language
from my ladylike little girl!  Nanki-Poo came into the room to see what the
yelling was about.  He didn't go over to the slider, and probably couldn't
see the outside cat from that angle.  He just sat down and watched Lindy.
Suddenly she turned around and saw him.  She ran over to him, bapped him a
few times, with a few cuss words thrown in, and then went back to the
slider.  The intruder was gone by that time, since he had jumped over the
block wall into the yard next door while she was bapping poor Nanki.

The only reason I can see for her attacking him was that he was handy, and
she would have had to go around and out the cat door to get at the outside
cat.