At the back of the yard, behind Brian's shop. Brian goes to the left, I go to the right to see who's fighting.
No one. I see Pancho at the top of the fence, hanging from the top, looking over. Brian saw Spot on top of the stuff that's stacked against the fence at the side of the shop, looking over the fence. (Remember, our fence has been modified so it's really hard for a cat inside to go outside, unless there's something the cat can climb and jump over, like a tree or a tractor.)
The cat fight wasn't in our yard. But we had a couple of interested observers. I asked Pancho what was going on and he told me. I didn't understand a meow he said, but I pretended I was interested. I learned how to do that when Brian started explaining things to me about the hydraulics he works on.
These guys are so funny.