🌀 Say hello to Tubular – the Parametric Shelf Marble Run! Turn boring shelves into an interactive physics playground. Optimized for IKEA IVAR (18mm) and 20mm PVC hoses, this modular kit lets you build wild tracks with loops & curves. 📐 100% Parametric: Customize board/hose size directly in your browser! 🚫 Support-Free: Easy printing to save your filament. 📦 Modular: Starting funnel, loops & connectors included. Check it out & show me your tracks! #Contests #ChildrensToys