B(n,t),           w = {A,B,C,D}   
B'(n,t),   n = 3, w' = {A',B',C'} = {3  · (B-A),   3  · (C-B),   3  · (D-C)}
B''(n,t),  n = 2, w'' = {A'',B''} = {2  · (B'-A'),   2  · (C'-B')}          
B'''(n,t), n = 1, w''' = {A'''}   = {1  · (B''-A'')}