grid.rect(gp=gpar(col="gray")) angle <- seq(0, 2*pi, length=50) grid.lines(x=seq(0.1, 0.5, length=50), y=0.5 + 0.3*sin(angle), arrow=arrow()) grid.segments(6:8/10, 0.2, 7:9/10, 0.8, arrow=arrow(angle=15, type="closed"))