matplotlib/matplotlib — pull request #3239 by mdboom (2014-07-12 18:27:06+00:00)
Title: Fix auto-closing in PolyCollection

As reported by @WeatherGod, the auto-closing code in PolyCollection always closes back to (0, 0) rather than the original point. Big problem. I guess most of our polys were origined at (0, 0) which is why we never noticed this.