plt.show() freezes Xcode indefinitely

For me, the plot command freezes up Xcode indefinitely everytime I try to use it. If I comment out the plt.show(), everything is fine but obviously nothing happens.

I'm on Xcode 7.1, OSX 10.11, using the default shipped python. All the necessary python libraries seem to be installed. Similar code from python in the terminal works well, but not inside lldb.
