The app uses a physical model to find the largest area triangle whose vertices lie on a smooth closed curve (defined by the red control points).
The triangle defined by the tangent lines at the vertices is displayed, along with its medians.
What do you notice about the maximum?

I saw a demo where a foam cube had a knitting needle inserted along the long diagonal, and was rotated by spinning the needle between the palms of the hands.
The sides of the cube formed a curve... in fact a portion of a hyperbola, as this video illustrates.