Yield left-to-right tie chains in expr.
abjad> notes construct.notes([0], [(5, 16), (1, 8), (1, 8), (5, 16)])
abjad> staff = Staff(notes)
abjad> tuplet = FixedDurationTuplet((2, 16), staff[1:3])
abjad> pitchtools.diatonicize(staff)
abjad> print staff.format
\new Staff {
c'4 ~
\times 2/3 {
c'16
d'8
}
e'8
f'4 ~
f'16
}
abjad> for x in iterate.tie_chains(t):
... x
...
(Note(c', 4), Note(c', 16))
(Note(d', 8),)
(Note(e', 8),)
(Note(f', 4), Note(f', 16))
Note that one-note tie chains yield the same as other tie chains.
Note also that nested structures are no problem.