function show3_post(p,c)
% display a geometric figure defined by points, p, in 
% homogeneous coordinates and connectivity, c, where
%   p(i,j):  i=point; j=coord (1=x,2=y,3=z,4=h)
%   c(i):    i=point (value>
%
axis('square');
maxp=max(p);
minp=min(p);
axis([minp(1),maxp(1),minp(2),maxp(2) minp(3) maxp(3)])
%
maxc=length(c)-1;
hold on;
i=2;
j=2;
x(1)=p(1,1);
y(1)=p(1,2);
z(1)=p(1,3);
while i <= maxc
   while c(i)>0 & i <= maxc
      x(j)=p(c(i),1);
      y(j)=p(c(i),2);
      z(j)=p(c(i),3);
      j=j+1;
      i=i+1;
   end;
   plot3(x,y,z)
   x=[]; y=[];z=[];
   x(1)=p(-c(i),1);
   y(1)=p(-c(i),2);
   z(1)=p(-c(i),3);
   j=2;
   i=i+1;
end;
hold off;
points3_post(p)
