over=: ({.;}.)@":@,                  功用函數, 會用即可，先不急著學。
   by=:  ' '&;@,.@[,.]                  

   primes=: 2 3 5
   i=: 0 1 2 3 4

   primes by i over primes */ i
+-+------------+
| |0 1  2  3  4|
+-+------------+
|2|0 2  4  6  8|
|3|0 3  6  9 12|
|5|0 5 10 15 20|
+-+------------+

   tba=: 1 : '[ by ] over x./'          表格副詞

   primes * tba i
+-+------------+
| |0 1  2  3  4|
+-+------------+
|2|0 2  4  6  8|
|3|0 3  6  9 12|
|5|0 5 10 15 20|
+-+------------+
   7 11 ^ tba i
+--+-------------------+
|  |0  1   2    3     4|
+--+-------------------+
| 7|1  7  49  343  2401|
|11|1 11 121 1331 14641|
+--+-------------------+