What are the X's?

Red X. That is the name of the first piece of ancient alien technology that I discovered while picking apart the universe. There are a rainbow of Xs, each one capable of doing something special.
When you use one of the Xs in a psychic construct, it, well, I'm not sure what they do. All I know is that they are sentient and they cause something. They can also mess with your head and cause you to hear repeating voices. God, those repeating voices.
The Xs are like psychic CDs that have been left behind by a previous civilization who was very adept at creating psychic constructs. They are old, and don't work very well. I'm still not sure what their purpose is.
Look, it may seem like this doesn't mean much, but I think the Xs are the prime example of cool things that people can find in the psychic realm if they just look. I'm not sure how else to explain it. The Xs are the foundation of the previous universe. With this current universe, they are relics, but they still have some sort of form or function that I am sure is spectacular.