The lab
Turn spin into shape.
Spin is what gives the pitch its direction. Turn the clock and watch the seam ball and catcher’s-eye plot redraw as ride, drop, arm-side run, or glove-side sweep.
Stock tilts
Illustrative clock positions, not claims about a specific pitcher.
Vertical shape
ride
ride, drop, or flat
Side shape
none
arm-side, glove-side, or true
Pure ride. The pitch holds above the spinless path.
A grip to study
Keep a sourced grip beside the experiment. Choosing a file leaves the spin tilt unchanged; the plot remains an illustrative model, not measured movement for that pitch.
A teaching model. Spin tilt sets the direction of the Magnus force: backspin creates ride, topspin creates drop, and sidespin creates run or sweep. This page describes shape only; it does not predict how far any arm moves a pitch.
The plot’s arm and glove sides are named from the ball’s point of view; which physical side that is flips with the pitcher’s hand.