I meandered down the... «Zero Sum Game»

I meandered down the sidewalk, keeping a sidelong view of Courtney`s house. The dark-suited men became points in motion, my brain extrapolating from the little I could see and hear, assigning probabilities and translating to expected values. As I drew up to the house, the highs and lows of conversation became barely audible, but I ran some quick numbers — to decipher the words, I`d have to be so close I`d be the most obvious eavesdropper in the world. The plot of half-hearted grass between the street and the houses didn`t have any handy cover I could use to sneak closer, either.
I ran my eyes over the surrounding scenery, a three-dimensional model growing in my head. A stone wall curved out from just behind Polk`s house and ended in a tumble at a vacant lot, and it very nearly fit the curvature of a conic.
Sound waves are funny things. They can chase each other over concave surfaces, create reinforcing concentrations of acoustics at the focus of an architectural ellipse or parabola. Some rooms are famous for the ability to whisper a word on one side and have it be heard with perfect clarity on the other.
I only needed a few more sounding boards.
I wandered back down the street and kicked at a trash can as I went by so it turned slightly. Ran my hand along the neighbor`s fence, pulling the gate closed with a click. Flipped up a metal bowl set out for stray cats with my foot so it leaned against a fire hydrant. Tossed a rock casually at a bird feeder so it swung and changed orientation. I ambled down the street twice more, knocking the detritus of the street around, making small changes. Then I ran my eyes back across the house, feeding in the decibel level of normal conversation.
Close. All I needed was an umbrella. It wasn`t raining, but plenty of cars were parked on the street, and I found what I needed after a quick survey of back windows. I jimmied my way in, retrieved the umbrella from the back seat, and left the car door cracked at an angle for good measure. Then I headed over to a tree at the edge of the next lot, one that stood exactly at the focus of my manyfactured acoustic puzzle, but up the umbrella, and listened.
The voices in Courtney`s house sprang up as if they were right next to me.