function K = LinearSpringAssemble(K,k,i,j)
% LinearSpringAssemble(K,k,i,j)

I = 2*i-1;
J = 2*j-1;

K(I,I) = K(I,I) + k(1,1);
K(I,J) = K(I,J) + k(1,3);
K(J,J) = K(J,J) + k(3,3);
K(J,I) = K(J,I) + k(3,1);

endfunction