2. More Varieties

Problem 2.1.
For any of the standard varieties considered it might be possible to study the projective dual. What can we learn from studying these objects? 
Problem 2.2.
What can we say about the convex hull of all the varieties we have considered? Can we give a good description of them?
Cite this as: AimPL: Algebraic vision, available at http://aimpl.org/algvision.