measure
stave
a d f g
stave
1 rest
measure
stave
1 rest
stave
1/4 a d f g
slur
starts above first note in first measure in first stave
and finishes at fourth unit in second measure in second stave
comment: "
As you see in the image below, the slur below thinks
that it includes units on first stave in second measure,
because we did not specify here a unit where it changes its stave.
"