Paper straws have an interesting spiral pattern and are easy to work with. It’s hard to make curved angles so they’re best used in straight lines. Plastic ones - now harder to find - are even softer, but have a ridged section that’s perfect to join parts at different heights or at angles. To make them more durable and rigid you can fill them with silicone, putty or rolled paper - if they crumple, then they’ll quickly lose any paint.