The actual Alexandre Alexeieff and Claire Parker demonstrate their miraculous apparatus for the assembled NFB animators. Very clear, very helpful. Also, very nitpicky! It’s almost impressive, how nitpicky they are. We forget that the people who invent or accomplish unprecedented and amazing things were probably all exacting, and maybe to a maddening degree.
On that same topic, with regard to maddening exactitude, you’ve still, always, got to remember what maddening exactitude can get you. What an invention!
Here is A&P’s most famous film production, showing what that invention was capable of: http://bit.ly/1sXWnLG