Love that you got inspired from the water bottle, very unique mechanism. 

• The folding tube is well represented. What material are you imagining in real life? For real-life materials, it’s essential to focus on durability and eco-friendliness. Options like recycled aluminum or carbon fiber composites could provide strength without excess weight. Alternatively, biodegradable plastics or thermoplastics could offer flexibility and a lower environmental impact. If the design requires transparency (to watch items pass through), consider recycled glass or a clear bio-resin.

• Since this concept aims to alleviate traffic and promote sustainability, clarifying how it would work on a large scale could help. Perhaps the system could rely on renewable energy sources (like solar-powered movement along the tube) or integrate with existing infrastructure in urban areas to minimize disruption.

• Just for clarity what is is transporting exactly? This is key as we might need to add safety measures or emergency exits.

Think of the location of this portal, where do you imagine this to be in a city? Maybe draw a diagram showing it’s use in realy life? Maybe  Placing the portals in high-traffic areas like business hubs or city centers could reduce congestion. Think of it as a direct link between major buildings, like corporate offices, transportation hubs, or nearby shopping areas.

Or Transportation Hubs: Imagine a portal connecting train stations, subway lines, or bus depots to reduce last-mile traffic and offer a quick, seamless way for people or packages to reach popular destinations without adding to street congestion.

Or University or Medical Campuses: Large campuses are often spread out, and a portal could transport people or materials efficiently across the area, especially in places where frequent transit is needed, like between hospitals or different university buildings.