from
perms
by Bill McKeeman even, odd, cyclical, unique permutations of a set of vectors
angles(e)
%ANGLES find the angles of an edge set
% ANGLES(E) finds vertex triples
%
function a = angles(e)
m = size(e,1);
a = [];
for i=1:m
for j=i+1:m
t = unique([e(i,:), e(j,:)]);
if numel(t)==3; a(end+1,:) = t; end
end
end