clear
close all
[a,b,c]=sphere(20);
figure
hold on
s2=sqrt(2);
axis([-2.5,2.5,-2.5,2.5,-2.5,2.5])
R=[1,1,0;1,-1,0;-1,-1,0;-1,1,0;0,0,s2;0,0,-s2];
for i=1:6
   contour3(.05*a+R(i,1),.05*b+R(i,2),.05*c+R(i,3));
end
II=[1,2,3,4,1,5,3,6,1,2,5,4,6,2];
Z=R(1,:);
for i=2:length(II)
   Z=[Z;R(II(i),:)];
end
plot3(Z(:,1),Z(:,2),Z(:,3),'r-')
hold off
