The Twist commands allow you to deform an object through rotation along an axis.

Create a surface, polysurface or mesh o be twisted.
Type twist
Rhino prompts you to provide a base point. This is the point from which your object will be scaled from. Its position will not change.
Rhino gives 2 options for the next input
Second Reference Point → the new location of the First Reference Point you will use to scale the entire object.
In the demonstration below, we scale the lower right point, to the midpoint of the front edge, meaning a scale factor of .5