Lego Great Ball Contraption (GBC) in my house. my own 17 modules tracking the blue and red balls. running at 1.0 balls/sec 500 balls size : 1.5m×6.5m path length : 31m construction time : 600 hours my blog http://legokarakuri.blog91.fc2.com/ 1. ball factory (inspired by superbird28) 2. zigzag stair 3. zigzag lift 4. pneumatic (sometimes spilling balls) 5. cup 6. screw T1 7. basket shooter 8.