1 1 1 1 2 1 1 3 3 1 ........................ = (0 0) (1 0) (1 1) (2 0) (2 1) (2 2) (3 0) (3 1) (3 2) (3 3) ........................
1 1 1 1 2 1 1 3 3 1 ........................
(0 0) (1 0) (1 1) (2 0) (2 1) (2 2) (3 0) (3 1) (3 2) (3 3) ........................