12) An Area Rotated Around an Axis

> restart;

> with(plots): with(plottools):

> rad1:=y->y^2+1:

> t:=tubeplot([y,0,0,y=-2..2], radius=rad1(y),
axes=none, labels=[x,y,z],
scaling=constrained, style=wireframe):

> a2:=polygonplot3d([seq([y/5,(y/5)^2+1,0],
y=-10..10)], style=patch):

> for i from 1 to 10 do
bpi:=display({t, rotate(a2,i*Pi/5,0,0)}):
od:

> display(seq(bpi,i=1..10), insequence=true,
orientation=[-166,141]);