
A = zeros(7,7);
A(1,2) = 1; A(1,6) = 1;
A(2,5) = 1; A(2,7) = 1;

A(3,6) = 1; A(3,4) = 1;

A(4,7) = 1;
A(6,7) = 1;

%% column version -- so need to transpose

A = A';
