#+property: var foo=1
#+property: var bar=2

#+begin_src emacs-lisp
  (+ foo bar)
#+end_src

#+results:
: 3

#+begin_src emacs-lisp
  (org-entry-get (point) "var" t)
#+end_src

#+results:
: foo=1, bar=2

* heading
  :PROPERTIES:
  :var:      foo=4
  :END:

#+begin_src emacs-lisp
  foo
#+end_src

#+results:
: 4

#+begin_src emacs-lisp
  (org-entry-get (point) "var" t)
#+end_src

#+results:
: foo=4