For anyone who has ever been to a LEGO convention, the sound of a GBC is pretty hard to miss. It’s not a very pleasant sound—in fact, it’s often quite deafening—and it’s almost always crowded with people admiring the different types of contraptions that slowly transport a crazy amount of LEGO footballs (soccer balls for our American readers) and basketballs around a never-ending loop. What is a GBC? GBC in the LEGO community stands for Great Ball Contraption. If you are new to GBCs, it’s a build (aka module) with moving parts that transports balls from one point to another. BrickNerd has a comprehensive article on the history of the GBC. The beauty of this concept is that if you put a bunch of modules alongside each other, the balls can be transported from module to module. If enough are connected, you get a loop that transports the balls in a...

