Three tangent lines meet at the "Center of Tangents" $C_t(t)$. Three normal lines meet at the "Center of Normals" $C_n(t)$. The points $C_t$ and $C_n$ are the end points of a diameter of the circumcircle of the triangle made by three masses. This is due to the fact $L=0, I=constant$. Large eight: The figure-eight orbit. Black points: The position of masses $q_i(t)$. Red lines: Tangent lines. They meet at $C_t(t)$. Blue lines: Normal lines. They meet at $C_n(t)$. Purple moving circle: The circumcircle. Purple point: The circumcenter. Hyperbola-like curves from inner to outer: Orbit of the circumcenter. Orbit of the "Center of Normals" $C_n(t)$. Orbit of the "Center of Tangents" $C_t(t)$. Small eight: The orbit of the "Center of Force". Yellow point: The "Center of Force".