Pronounced as one letter, And written with three, Two letters there are, And two only in me. I’m double, I’m single, I’m black, blue, and gray, I’m read from both ends, And the same either way. What am I?

I stand alone yet never lone, Surrounded full yet on my own. A dot upon the boundless blue, Or key that floats in chains anew.

I lie flat, yet cover well, a quiet guardian for feet and tale. A tapestry of fibers underfoot, where crumbs and tales often root.

You pump me to get swole. To find me you make a big hole. Tony Stark is this type of man. Make steel with carbon? Yes I can.

I start when you close, to track that which you hold. A stores system is not complete without me, as you don't know how many you hold. So go and count, each item must match, that from the corporate overlords.