\begin{Schunk}
\begin{Sinput}
> x0 <- c(-1, -4, 4.5)
> y0 <- c(-1, -4, -8)
> x1 <- c(2, -2, -3)
> y1 <- c(4, 4, 18)
> mylengths <- c(0.2, 0.3, 0.15)
> mycodes <- c(3, 2, 1)
> bdraw()
> arrows(x0 = x0, y0 = y0, x1 = x1, y1 = y1, length = mylengths, code = mycodes)
\end{Sinput}
\end{Schunk}
