At the moment, we can produce three different objects by tapering a torus. We make torus -> circle by reducing the minor radius to zero. We make torus -> sphere by reducing the major radius. And we make torus -> point by reducing (or increasing) both radii simultaneously.

Now, there is a fourth object we can make, by reducing one radius while simultaneously increasing the other.

We would start with a circle, i.e. a torus with a minor radius of 0. Then we increase the minor radius and decrease the major radius while going up the w-axis. Eventually we end up with a sphere, i.e. a torus with a major radius of 0.

I don't think it's a good idea to add this to the official list of tapertopes, but it's an interesting object. It's RNS representation might be (2<sup>1</sup>1)<sup>-1</sup> or (2<sup>-1</sup>1)<sup>1</sup>. It could also be called "circle -> sphere via torus"