What do you call such a figure below and how to parametrize such kind of curve?
1 Answer
$\begingroup$
$\endgroup$
This looks like a variant of the dumbbell curve (see e.g. http://mathworld.wolfram.com/DumbbellCurve.html) This one could be parametrized for the upper part by $$x(t)=t,\ y(t)=(t^2 + 0.5)\sqrt{1 - t^2}$$ and the lower part by $$x(t)=t,\ y(t)=-(t^2 + 0.5)\sqrt{1 - t^2}$$ for $t\in[-1,1]$. Of course you can change the $0.5$ to a different positiv value to obtain different shapes.