not right.rs

    pub fn tick(sprite: &mut SpriteDescription, particle: &mut Particle, delta: f32) {
        let length_squared = particle.pos.x * particle.pos.x + particle.pos.y * particle.pos.y;
        let length = f32::sqrt(length_squared);
        let norm = particle.pos / length;
        let norm_squared = particle.pos / length_squared;
        particle.acceleration = -(norm * (Self::G * Self::MASS)).div_element_wise(norm_squared);
        particle.velocity += particle.acceleration;
        particle.pos += particle.velocity;

        let velocity = particle.velocity + particle.acceleration * delta;
        let position = particle.pos + velocity * delta;
        sprite.set_pos(position.extend(0.0));
    }

Fix norm_squared