y:=r*cos(t);

z:=r*sin(t);

x:=y^2+z^2;

p1:=plot3d([x,y,z],r=abs(cos(t))..1,

t=0..2*Pi,scaling=constrained,

color=red,grid=[31,101]):

with(plots):

x:=r*cos(t);

z:=r*sin(t);

y:=x^2+z^2;

p2:=plot3d([x,y,z],r=abs(cos(t))..1,t=0..2*Pi,scaling=constrained,color=green,grid=[31,101]):

p3:=display(p1,p2):

with(plottools):

p4:=reflect(p3,[0,0,0]):

z:=cos(phi);

r:=sin(phi);

x:=r*cos(theta);

y:=r*sin(theta);

solve(x+z=1,phi);

s:=arctan(2*cos(theta)/(1+cos(theta)^2),-(cos(theta)^2-1)/(1+cos(theta)^2));

p1:=plot3d([x,y,z],theta=0..2*Pi,phi=abs(s)..Pi/2,scaling=constrained,grid=[101,31]):

with(plottools):

with(plots):

q1:=translate(p1,0,0,-1):

q2:=rotate(q1,0,Pi/2,0):

q3:=rotate(q1,0,Pi,0):

q4:=rotate(q1,0,3*Pi/2,0):

with(plots):

p1:=tubeplot([1,-1,t],t=-1..1,grid=[5,51]):

with(plottools):

p2:=rotate(p1,2*Pi/3,[[0,0,0],[1,1,1]]):

p3:=rotate(p1,4*Pi/3,[[0,0,0],[1,1,1]]):

with(plots):

p1:=tubeplot([t,0,0],t=-1..1,radius=t,grid=[5,51]):

with(plottools):

p2:=rotate(p1,0,Pi/2,0):

p3:=rotate(p1,0,0,Pi/2):

with(plots):

p1:=tubeplot([-t,-t,-t],t=0..1,

radius=sqrt(6)*t,grid=[5,51],

scaling=constrained,color=red):

p2:=tubeplot([-t,t,t],t=0..1,

radius=sqrt(6)*t,grid=[5,51],

scaling=constrained,color=green):

p3:=tubeplot([t,-t,t],t=0..1,radius=sqrt(6)*t,

grid=[5,51],scaling=constrained,color=blue):

p4:=tubeplot([t,t,-t],t=0..1,radius=sqrt(6)*t,

grid=[5,51],scaling=constrained,color=yellow):

with(plots):

p1:=tubeplot([t,t,t],t=0..1,radius=sqrt(3/2)*t,grid=[5,51],scaling=constrained,color=red):

p2:=tubeplot([-t,t,t],t=0..1,radius=sqrt(3/2)*t,grid=[5,51],scaling=constrained,color=green):

p3:=tubeplot([t,-t,t],t=0..1,radius=sqrt(3/2)*t,grid=[5,51],scaling=constrained,color=blue):

p4:=tubeplot([-t,-t,t],t=0..1,radius=sqrt(3/2)*t,grid=[5,51],scaling=constrained,color=yellow):

with(plottools):

q1:=display(p1,p2,p3,p4):

q2:=reflect(q1,[0,0,0]):

x:=r*2*cos(t);

y:=r*sin(t);

z:=4-y^2;

p1:=plot3d([x,y,z],r=0..1,t=0..2*Pi,

scaling=constrained,color=red,grid=[11,101]):

z:=x^2+3*y^2;

p2:=plot3d([x,y,z],r=0..1,t=0..2*Pi,

scaling=constrained,color=green,grid=[11,101]):

with(plots):