pub trait Flowfield2D {
// Required methods
fn get_vec(&mut self, x: f32, y: f32) -> Vector2<f32>;
fn get_normalized_vec(&mut self, x: f32, y: f32) -> Vector2<f32>;
fn get_perp_vec(&mut self, x: f32, y: f32) -> Vector2<f32>;
fn get_perp_normalized_vec(&mut self, x: f32, y: f32) -> Vector2<f32>;
fn add_pole(&mut self, pole: Pole2D);
}