6 Ties are strictly horizontal. They are placed in between note heads.
7 The horizontal middle should not overlap with a staffline.
16 %b2~b4~b8~b16~b32~b64 r64\break
17 %a2~a4~a8~a16~a32~a64 r64
19 d1 ~ d2~d4~d8~d16~d32~d64 r64\break
20 a1~ a2~a4~a8~a16~a32~a64 r64
21 %c2~c4~c8~c16~c32~c64 r64