Morrie’s Law

\displaystyle \cos \left ( 20^{\circ} \right ) \cdot \cos \left ( 40^{\circ} \right ) \cdot \cos \left ( 80^{\circ} \right ) = \frac{1}{8}

Richard Feynman was so struck by this fact that he remembered ever afterward where he had learned it — from his childhood friend Morrie Jacobs as the two stood in Morrie’s father’s leather shop in Far Rockaway, Queens.