When trying to call plt.show() to display a generate QuadMesh using the MacOSX backend, an error complaining about "TypeError: only length-1 arrays can be converted to Python scalars" is generated. The following gist contains two files: 1) a self contained example that will generate the error and 2) the Traceback generated. For completeness, the full hash of the commit I'm using (pulled early today) is found in the first line of the second file.

https://gist.github.com/3087990

I should add that switching to using plt.contourf() instead of pcolormesh does not error. This error does not occur when using a different backend.