More Pies, Roses and Thorns

Continuing the hunt for ways to show headwind, rather prettier are these version, using an explicit geom_polygon to construct triangles.

In the first version, I'm using both transparency and thickness to code the number of observations (frequency that the wind was in this direction). I think this looks like thorns. Haven't worked out why the axis transform should put the twist on the triangles. Suggestions welcome!

In the second version, I've stuck to fixed width. This is more like the diaphragm of a camera, or a daisy.