+/*
+ START is part where stem reaches `last' head.
+ */
+Drul_array<Note_head*>
+Stem::extremal_heads () const
+{
+ const int inf = 1000000;
+ Drul_array<int> extpos;
+ extpos[DOWN] = inf;
+ extpos[UP] = -inf;
+
+ Drul_array<Note_head *> exthead;
+ exthead[LEFT] = exthead[RIGHT] =0;
+