zpg / accum.

: incf  ( addr -- )  1 swap +! ;
: incf. ( addr -- )  dup incf ? ;
: accumulator ( n -- xt )  here >r , :noname r> postpone literal postpone incf. postpone ; ;

: create-accumulator
    accumulator create , does> @ execute ;

5 create-accumulator five++
11 create-accumulator eleven++