startup preneur on Instagram: "This creator spent months trying to build a fully working mechanical marble clock using nothing but 3D printed parts. What looked simple at first quickly turned into a massive challenge. Tracks jammed, lifts failed, and whole sections had to be reprinted and hand-finished just to get the timing right. After countless fixes, the lift system and gravity circuit finally started running the way he imagined. Now he’s working on the marble selector, pushing to finish the