}
/// A parabola in 3D space; used to model the motion of a single body between
/// force calculations.
pub struct Parabola {
    a: V3,
    b: V3,
    c: V3,

impl Parabola {
    pub fn interpolate(&self, t: f64) -> V3 {
        self.a * t * t + self.b * t + self.c
    }
}