Tangent indicatrix

In differential geometry, the tangent indicatrix of a closed space curve is a curve on the unit sphere intimately related to the curvature of the original curve. Let $\gamma(t)\,$ be a closed curve with nowhere-vanishing tangent vector $\dot{\gamma}$ . Then the tangent indicatrix $T(t)\,$ of $\gamma\,$ is the closed curve on the unit sphere given by $T = \frac{\dot{\gamma}}{|\dot{\gamma}|}$ .