New in version 2.0.
Yield all positive integer pairs in Cantor diagonalized order:
abjad> from abjad.tools import durationtools
abjad> generator = durationtools.yield_all_positive_integer_pairs_in_cantor_diagonalized_order()
abjad> for n in range(16):
... generator.next()
...
(1, 1)
(2, 1)
(1, 2)
(1, 3)
(2, 2)
(3, 1)
(4, 1)
(3, 2)
(2, 3)
(1, 4)
(1, 5)
(2, 4)
(3, 3)
(4, 2)
(5, 1)
(6, 1)
Return pair generator.