1434.sagews

##A horn
r,theta,z=var('r'),var('theta'),var('z');
H=parametric_plot3d([z,0.5*(e^z+e^(-z))*sin(theta), 0.5*(e^z+e^(-z))*cos(theta)],(theta,0,2*pi),(z,0,2), frame=False, color='red',opacity=0.5);
show(H)

##An egg (not a very good one)
x=var('x');
C1=plot(sqrt(x),(x,0,4),color='blue');
C2=plot(sqrt(4-(x-4)^2),(x,4,4+sqrt(4)),color='blue');
show(C1+C2,aspect_ratio=1)

r,theta,z=var('r'),var('theta'),var('z');
S1=parametric_plot3d([sqrt(4)+4-r^2,r*sin(theta), r*cos(theta)],(r,0,sqrt(4)),(theta,0,2*pi), frame=False, color='blue',opacity=0.7);
S2=parametric_plot3d([sqrt(4)-sqrt(4-r^2),r*sin(theta), r*cos(theta)],(r,0,sqrt(4)),(theta,0,2*pi), frame=False, color='blue',opacity=0.7);
show(S1+S2)