In this other question the user asks for a parametric curve and "imposing" one curve on another. You can find a demonstration here.
I have been meaning to use the tangent to answer a similar question on how to find a reflected curve across another and have such a desmos demonstration. However I am not sure what the equations should turn out to be in that case.
By reflecting curve $F$ across $G$, I mean that for every point of $G$, we calculate the normal vector, and copying the intersection point between the normal line and curve $F$ at the same distance but on the opposite side of the curve $G$ along the normal direction. The resulting curve $F'$ of all those points is the "reflection" of $F$ along $G$.
This can also be thought of as a generalization of the function inverse. When we let the curve we are reflecting over be the $y=x$ line, the reflection $F'$ is precisely the inverse of the curve $F$, in the sense that the $x$ and $y$ coordinates of the points have been swapped.