3 Slurs can be forced to always attach to note heads.
8 \property Voice.Slur \set #'direction = #1
9 \property Voice.Slur \set #'attachment = #'(head . head)
10 g''16()g()g()g()d'()d()d()d
13 \paper { linewidth = -1.; }
16 \notes\relative c \fragment