After my experiences at the full week of Lego World Utrecht I decided to do a complete redesign and rebuild of my stand alone GBC version of the Akiyuki based marble run. Only the method of clamping the tubes as tracks is the same as in the previous version. The ball shooter had proven it's reliability during Lego World and because of the improved design only one shooter is used. Very pleased with the now reliable result. https://www.youtube.com/watch?v=olx4JmtnVq4