How do you make collapsible cubes, circles and squares for easy pack up for your Tube illusions like Cube Zag, Jam, etc? Is this better made in wood, plastic or metal? Do you use pin hinges or screws?

I'd say you're better off with bolts or loose pin hinges instead of screws- screws will eventually wear out the wood after constant assembly/disassembly, and it's much easier to replace bolts and hinges- with screws you'd need to replace much of the illusion.

As for wood, plastic, or metal, it's a question of cost vs. weight vs. durability. High quality wood should last as long as metal or plastic. Metal is heavier, though you can use thinner sheets (so it's sometimes necessary). Plastic is probably the lightest, but not as scratch-resistant (though solid colors may not show scratches as readily as scratched painted wood), and definately the most expensive to work with. I personally use wood, but my resources are more limited than some (I don't have a few thousand dollars to spend building an illusion... yet.) I'm sure some of the more experienced builders may have better advice.

Ensign Red Shirt... don't beam down to that planet!!!!!

Sorry, I couldn't resist.

For collapsible cubes, circles and squares, I would use a very lightweight plastic, since you want to be able to collapse these materials. Go down to your local fabric or crafts store and look around. I don't know what they are used for but I have seen see-through lightweight plastic collapsible cubes, circles, triangles, rectangles and squares at these stores.