%% 
X = randn(50,2);

%%
A = [ones(10) zeros(10) zeros(10);
    zeros(10) ones(10) zeros(10);
    zeros(10) zeros(10) ones(10)];
A(31,10) = 1;
A(10,31) = 1;
A(31,20) = 1;
A(20,31) = 1;
A(31,30) = 1;
A(30,31) = 1;
A(29,31) = 1;
A(31,29) = 1;
L = nlaplacian(A);
[V,D] = eig(full(L));

%%
plot(V(:,2),V(:,3),'.')
