Ok to make it foldable this is my take on it. each color is its own piece so you have 3 pieces attached at the top ring (and can swivel) and the square pieces to firm it all up. if you notice there is a white slash on the pics on both sides of the uprights this is revent the uprights from sliding around this can be done with a thick washer welded or just a weld. So you would drop the blue square from the top while holding the uprights separated. If I was even remotely a welder I would try this as I am positive it would work and it would fold down nicely as well.
If this plan works well for you and you appreciate my idea you can always make me one and charge me shipping only,,,,,,,