\begin{tikzpicture} 
    \node at (9,0) (63) {6,3};
    \node at (7,0) (73) {7,3};
    \node at (6,1) (72) {7,2};
    \node at (5,2) (71) {7,1};
    \node at (4,3) (7) {7};
    \node at (5,4) (6) {6};
    \node at (6,5) (5) {5};
    \node at (7,6) (4) {4};
    \node at (7,4) (51) {5,1};
    \node at (6,3) (61) {6,1};
    \node at (7,2) (62) {6,2};
    \node at (11,0) (53) {5,3};
    \node at (13,0) (43) {4,,3};
    \node at (15,0) (33) {3,3};
    \node at (9,2) (52) {5,2};
    \node at (9,4) (41) {4,1};
    \node at (9,6) (3') {3};
    \node at (11,2) (42) {4,2};
    \node at (11,4) (31') {3,1};
    \node at (11,6) (2') {2};
    \node at (13,2) (32') {3,2};
    \node at (13,4) (21') {2,1};
    \node at (13,6) (1') {1};
    \node at (15,2) (22') {2,2};
    \node at (15,4) (11') {1,1};
    \node at (15,6) (0') {0};
    \draw[->, ultra thick] (73)--(72);
    \draw[->] (73)--(63);
    \draw[->] (72)--(71);
    \draw[->, ultra thick] (72)--(62);
    \draw[->] (71)--(7);
    \draw[->] (71)--(61);
    \draw[->] (7)--(6);
    \draw[->, ultra thick] (62)--(61);
    \draw[->] (62)--(52);
    \draw[->] (61)--(6);
    \draw[->, ultra thick] (61)--(51);
    \draw[->] (6)--(5);
    \draw[->, ultra thick] (51)--(5);
    \draw[->] (51)--(41);
    \draw[->, ultra thick] (5)--(4);
    \draw[->] (63)--(53);
    \draw[->] (63)--(52);
    \draw[->] (52)--(42);
    \draw[->] (52)--(41);
    \draw[->] (41)--(31');
    \draw[->] (41)--(3');
    \draw[->, ultra thick] (3')--(2');
    \draw[->, ultra thick] (4)--(3');
    \draw[->] (53)--(43);
    \draw[->] (53)--(42);
    \draw[->] (42)--(32');
    \draw[->] (42)--(31');
    \draw[->] (31')--(21');
    \draw[->] (31')--(2');
    \draw[->, ultra thick] (2')--(1');
    \draw[->] (43)--(33);
    \draw[->] (43)--(32');
    \draw[->] (32')--(22');
    \draw[->] (32')--(21');
    \draw[->] (21')--(11');
    \draw[->] (21')--(1');
    \draw[->] (33)--(22');
    \draw[->] (22')--(11');
    \draw[->] (11')--(0');
    \draw[->, ultra thick] (1')--(0');
    
    \end{tikzpicture}