Riddle answer consists of 4 characters and was created by Guest
In the heart of a labyrinth, I am not found, yet I surround the center, unbound. I am always coming but never arrive, I have a head, but never weep, I have a bed, but never sleep, I have a mouth, but never speak. I am a force that's felt, but never seen, I am a presence that's known, but never gleaned. What am I?