Task

Produce a formatted   12×12   multiplication table of the kind memorized by rote when in primary (or elementary) school.



Only print the top half triangle of products.




  [ swap number$ 
    tuck size - 
    times sp echo$ ] is echo-rj ( n n --> )
 
  say "  * |"
  12 times [ i^ 1+ 4 echo-rj ] cr
  say " ---+" 
  char - 48 of echo$ cr
  [ 12 times
     [ i^ 1+ 
       dup 3 echo-rj
       say " |"
      12 times
        [ i^ 1+ 
          2dup > iff
            [ drop 4 times sp ]
          else 
            [ dip dup 
              * 4 echo-rj ] ] 
       cr drop ] ]