How to draw a directed arc with an initial point $(x_i,y_i)$, a terminal point $(x_t,y_t)$, and another given, intermediate point $(x_m,y_m)$ on the arc (say in the middle of the arc)? For instance, we may have $(x_i,y_i)=(0,0)$, $(x_t,y_t)=(2,0)$, and $(x_m,y_m)=(1,1/3)$.
I have noticed the nice answers to a related problem. However, with my very limited proficiency in Mathematica, I do not see a good way to modify those answers to get what I need here. I can certainly draw an arc -- but how to attach an arrow to it nicely?