Ziggurat becomes Pyramid.  In this sketch you can drag the slider and increase the levels of the ziggurat (while keeping the height constant) to approximate a pyramid.

Revolving around the x-axis.  This sketch shows a curve in the xy-plane and then the same curve in space.  You can drag n, show the rectangle sum, show the sequence of cylinders, and show the actual surface.  (Dragging n is key!)