Answer:
In we go, out we go. All around and in a row. Always, always steady flow. When we'll stop, you'll never known. In we go, out we go.
Held firmly in the hands, like a sword it cuts deep. Bloodless strokes, all, then forward we leap.
Being able to interpret the letters on this screen proves that you have this quality.
My life can be measured in hours. I serve by being devoured. Thin, I am quick. Fat, I am slow. Wind is my foe.
I am two-faced but bear only one. I have no legs but travel widely. Men spill much blood over me. Kings leave their imprint on me. I have greatest power when given away, yet lust for me keeps me locked away.
I have two bodies joined together as one. When standing still I run and run.
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?