I am building a device out of 1/4" brass tubing. I need to join lengths in such a way as to allow the tubes to flex up to 135 degrees from straight. I haven't been able to figure out how to get that much rotation from a ball joint without the joint falling apart. See attached diagram below for what I'm trying to do. The posts fold back on themselves until they are a mere 45 degrees from W. Note that the joint needs to be entirely symmetrical - i.e. W is not special, it is identical to X Y and Z. (I could take the joint by itself, toss it in the air and catch it and not know the difference in orientation.) The one solution that might do it would be to make them all universal joints, like in the drive shaft of a car, like this:http://upload.wikimedia.org/wikipedia/commons/b/b5/Universal_joint.gif but I don't have the room for 4 universal joints in that little space. Looking for alternate ideas. Would accept off-the shelf parts or build by hand. Thoughts?