Can you explain the problem. Walking from [3 4 2] to [0 0 2] gives (3-0)+(4-0) = 7 units. Then from [0 0 2] to [0 1 2] gives 1 unit. From [0 1 2] to [1 1 2] gives 1 unit and finally from [1 1 2] to [1 1 20] gives 18 units. So sum of distance is 7+1+1+18 = 27. Is it right?