Build Great Ball Contraptions from existing LEGO sets

 
Explore the wonderful world of Great Ball Contraptions and start engineering with our building instructions right away! All our models are so called Alternate Builds, which are models entirely made from parts of an existing LEGO set. This makes it really easy to get yourself started today. What is a GBC you ask? In short: an infinite ball track and the greatest feat of LEGO engineering but it is so much more than that. Learn more! Give our free building instructions a try first.

 
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