Ever need a oblong curve but an ellipse was to sharp on the ends?
Give this equation curve a try.
R2 is a key element. Odd shapes start to appear if you change this.
You can scale the entire object by using "theta=(2+cos(t*180+90)^2)/<scalefactor>
Also note that the value for t = -1 to 1 using cylindrical coordinates
The formula can probably be duplicated in other ways.
I simply wanted to provide a means to create an oblong curve with continuous curvature change that did not simply put straight and circular elements together.
Enjoy.