Looking at Pitch Movements

Here's a look at horizontal pitch movement against vertical pitch movement. The units are in inches, and is compared to a "theoretical pitch thrown at the same speed with no spin-induced movement." And since I'm on the subject of swinging third strikes, here are the movements of four-seam fastballs, changeups, curveballs, and sliders on those types of pitches between 2007-2009:

I used the hexbin plotting function in order to group the pitches by hexagonal points. I put the LHPs and RHPs together, so if you take a look at fastballs, changeups, and curveballs, you can see two focal points. Fastballs seem to have "rising movement," so there is positive vertical movement here for pitches that get pitchers to swing. On the other hand, swinging strike-inducing curveballs drop, showing negative vertical movement.