Copied from the original comment on LightTable/LightTable#1641:
Hi there,
Evaluating python [on mac osx] has erratic (on my machine at least). It works sometimes (http://pastebin.com/Yzd2xFvy) while it does not work many other times (blocks at the left hand corner just keep rotating) (http://pastebin.com/5Su6dhg3)
I will be very thankful to you for your help in resolving this.
Copied from the original comment on LightTable/LightTable#1641: