An exemplary display of the latter is The Citadel. Over the course of three years, redditor [Shadowman39] pieced together this monstrous K’nex structure. With over 17 different paths(!), ...

and building a prototype with the K'nex. Some students say the prep work was easy. "We started in November. It took us quite a long time to build, but we got it managed to get a good, simple look ...