Duplo compatible marble pump

Did you already have fun with the duplo marble run (http://www.thingiverse.com/thing:159219)?
Then you are ready for much more fun and challenge!
Extend your marble run with a marble pump inspired by the great work of Matthias Wandel (http://woodgears.ca/marbles/lifter.html).
Push up marbles using the lever. (No motor.) The drop-block mechanism prevents the marbles from falling back.
Please read the instructions.
OpenSCAD files are included.
See marble pump in action:
http://youtu.be/2z1Rwl-ASx4
http://youtu.be/mFvod_YRR_w