I have a collection of 2d points xy.

Instead of simply plotting the points,

I'd like to plot a collection of arrows

that goes from each point to the next.

The "from" is easy of course;

the "to" is the problem.

I think I should be able to use quiver,

but I'm not getting it quite right.

E.g.,

x,y = zip(*xy)

u,v = np.diff(x), np.diff(y)

quiver(x[:-1], y[:-1], u, v, angles='xy')

looks like a start but does not get there.

I guessed that `scale=1` would complete

the picture, but that just showed that I

misunderstood `scale`.

Suggestions?

Alan Isaac