Answer:
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.
Power enough to smash ships and crush roofs. Yet it still must fear the sun.
What measures out time. Until in time all is smashed to it?
One by one we fall from heaven down into the depths of past, And our world is ever upturned so that yet some time we’ll last.
A harvest sown and reaped on the same day In an unplowed field, Which increases without growing, Remains whole though it is eaten Within and without, Is useless and yet The staple of nations.
You use it between your head and your toes, the more it works the thinner it grows.
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?