Draw arrow
myarrow(
  from,
  to,
  lwd = 1,
  adjust = 1,
  label = "",
  label.pos = 0.5,
  arr.pos = NULL,
  radx = 0.1,
  rady = 0.06,
  xadj = NULL,
  yadj = NULL,
  curve = 0,
  dd = 0,
  ...
)coordinates (x,y) of the point *from* which to draw arrow.
coordinates (x,y) of the point *to* which to draw arrow.
line width
adjust position
label
label position
arrow position
horizontal radius of the box.
vertical radius of the box.
numeric x adjustment
numeric y adjustment
integer relative size of curve (fraction of points distance)
length of segment arm, directed away from endpoints.
Further argument to be passed to straightarrow()