The circle passing through the isodynamic points S and S' and the triangle centroid G of a triangle Δ A_1 A_2 A_3. The Parry circle has circle function l = - (b c(b^2 + c^2 - 2a^2))/(3(a^2 - b^2)(a^2 - c^2)), which does not correspond to any noted triangle center.

isodynamic points | Kiepert parabola | Parry point | triangle centroid