Greetings. It's almost midnight, which is kinda early for me to be about
to go to bed, but I thought I'd scribble something here first. Try this

One has a head without an eye,
the other an eye without a head.
You may find the answer if you try.
Half the answer hangs upon a thread.

No, I didn't write it. Yes, I know the answer. If you're stuck, email me.