function p = rotation(xangle,zangle,points)
%
p = points;
cz = cos(zangle); sz = sin(zangle); sx = sin(xangle); cx = cos(xangle);
for index = 1:12
  x = points(index,1)*cz + points(index,2)*sz;
  y = -points(index,1)*sz + points(index,2)*cz;
  z = points(index,3);
  p(index,:) = [x,y*cx-z*sx, y*sx+z*cx];
end
