Arrow plot in 2d using the grid package
arrow_2d_grid(
  zargs,
  loc = c(0.5, 0.5),
  angle = 60,
  length = 0.2,
  group... = list(cex = 0.66),
  draw = FALSE,
  ...
)grob (invisibly)
argument list as passed from zenplot()
(x,y)-location of the center of the arrow
angle from the shaft to the edge of the arrow head
length of the arrow in [0,1] from tip to base
list of arguments passed to group_2d_grid (or NULL)
logical indicating whether drawing should take place
additional arguments passed to gpar()
Marius Hofert and Wayne Oldford
Other default 2d plot functions using the grid package: 
axes_2d_grid(),
density_2d_grid(),
group_2d_grid(),
label_2d_grid(),
points_2d_grid(),
qq_2d_grid(),
rect_2d_grid()
Other default 2d plot functions: 
arrow_2d_graphics(),
arrow_2d_loon(),
axes_2d_graphics(),
axes_2d_grid(),
axes_2d_loon(),
density_2d_graphics(),
density_2d_grid(),
density_2d_loon(),
extract_2d(),
group_2d_graphics(),
group_2d_grid(),
group_2d_loon(),
label_2d_graphics(),
label_2d_grid(),
label_2d_loon(),
points_2d_graphics(),
points_2d_grid(),
points_2d_loon(),
qq_2d_graphics(),
qq_2d_grid(),
rect_2d_graphics(),
rect_2d_grid(),
rect_2d_loon()