Answer:
Twigs and spheres and poles and plates. Join and bind to reason make.
What does everyone know how to open but not how to close?
What month of the year has 28 days?
Hard to catch, easy to hold. Can't be seen, unless it's cold.
I'm not really more than holes tied to more holes. I'm strong as good steel, though not as stiff as a pole.
They are many and one, they wave and they drum, Used to cover a state, they go with you everywhere.