Fig 1Quadratic rangeKeys 1–4 rest · gravity · angle · starta -4.9 · b 11.9 · c 1.4 · peak 8.6 · lands 27.2
Ball, paper curve, apex needle, landing pin — all from h(t)=at²+bt+cKnobs A gravity, B up-speed, C start heightA spring launcher fires a ball across a paper screen. Knob A is a (how hard gravity bends the path), B is b (up-speed), C is c (start height). The curve, the peak dial and the floor pin are the same quadratic, not captions.