/mk-acc  {             % accumulator generator
  {0 add 0 0 2 index put}
  7 array copy
  dup 0 4 -1 roll put
  dup dup 2 exch put
  cvx
}  def

% Examples (= is a printing command in PostScript):
/a 1 mk-acc def        % create accumulator #1, name it a
5 a =                  % add 5 to 1, print it
10 mk-acc              % create accumulator #2, leave it anonymous on the stack
2.71 a =               % add 2.71 to 6, print it
dup 3.14 exch exec =   % add 3.14 to 10, print it
dup 100 exch exec =    % add 100 to 13.14, print it
12 a =                 % add 12 to 8.71, print it
                       % accumulator #2 is still available on the stack