Column Block Subtraction

   var1 var2 var3 var1.bis var2.bis var3.bis var_diff_1 var_diff_2 var_diff_3
1     1    3    9        3        4        9          2          1          0
2     4    9    8        2        2        6         -2         -7         -2
3     7    7    1        8        5       10          1         -2          9
4     5    1   10        4        7        7         -1          6         -3
5    10    8    3       10        6        5          0         -2          2
6     9   10    7        1        3        1         -8         -7         -6
7     3    5    4        7        8        8          4          3          4
8     8    2    5        5        1        4         -3         -1         -1
9     2    4    2        6       10        3          4          6          1
10    6    6    6        9        9        2          3          3         -4