private float __seek(float len_, float d, float t0 = 0.5f, float td = 0.25f) { float lent0 = integrate(t0); if (Mathf.Abs(len_ - lent0) < d) return t0; else return __seek(len_, d, (lent0 < len_) ? t0 + td : t0 - td, td / 2.0f); }